Balancing EU Autonomy and International Obligations: The Evolution of Environmental Access to Justice in EU Law

Table of Contents: 1. Introduction. – 2. The autonomy of EU law and the integration of international environmental law. – 3. The Aarhus Convention and the EU: procedural autonomy at the intersection of legal orders. – 4. The CJEU’s engagement with the Aarhus Convention and ACCC Findings: navigating internal and external autonomy. – 4.1. The impact of the Aarhus Convention on EU legal remedies. – 4.2. The CJEU and ACCC Findings: selective dialogue and doctrinal distance. – 5. Legislative responses to ACCC Findings: between compliance and control. – 5.1. Strategic engagement at the Aarhus MOP: participation, resistance and autonomy requests. – 5.2. Reforming the Aarhus Regulation: expansion and remaining gaps. – 5.3. Access to justice in state aid: the next frontier. – 6. Conclusion.

Abstract: This Article examines the evolution of access to justice in environmental matters within the European Union (EU) legal framework. It highlights contemporary developments, including the expanded use of internal administrative review following the 2021 amendment to the EU’s Aarhus Regulation and the 2025 reforms regarding state aid decisions. These legislative developments respond to findings by the Aarhus Convention Compliance Committee (ACCC) that the EU system fails to provide adequate and effective remedies for challenging potential environmental law violations. Against this backdrop, the analysis explores the dynamic tension between the autonomy of EU law and international legal obligations, investigating how the Aarhus Convention has acted as a catalyst for change, compelling the EU to reconsider its own legal processes, particularly in relation to access for environmental Non-Governmental Organisations (NGOs). The Article explores the pivotal role of the Court of Justice in managing the tension between preserving the autonomy of EU law and engaging constructively with international environmental norms. Ιt argues that while safeguarding institutional autonomy and the Court’s jurisdiction is a legitimate concern, excessive self-reference risks undermining the EU’s international credibility and commitment to the rule of law. This Article demonstrates the importance of carefully balancing autonomy concerns with meaningful integration of international environmental standards towards ultimately strengthening the EU legal order and empowering NGOs as environmental guardians.

Keywords: access to justice – autonomy of EU Law – Aarhus Convention – Aarhus Convention Compliance Committee – direct effect – consistent interpretation.

1.   Introduction

This Article examines the evolution of access to justice in environmental matters within the European Union (EU) legal framework. ‘Autonomy’ serves as the key conceptual thread underpinning this evolution. Traditionally, access to courts in the EU has been governed by domestic procedural rules, with national legislatures determining who has a legitimate interest to litigate. However, in the environmental field, the integration of the Aarhus Convention on Access to Information, Public Participation in Decision-making and Access to Justice in Environmental Matters (Aarhus Convention)[1] into EU law, combined with the principle of effective judicial protection under Article 19 of the Treaty on the European Union (TEU)[2] and the right to an effective remedy under Article 47 of the Charter of Fundamental Rights,[3] has constrained the procedural autonomy of both the Member States and the EU. It imposes obligations aimed at ensuring broad access to justice, particularly for environmental Non-Governmental Organisations (NGOs). The legislative developments in relation to the Regulation on the application of the provisions of the Aarhus Convention to EU institutions and bodies (Aarhus Regulation)[4] and its internal administrative review mechanism reveal the dynamic interplay between the EU’s need to comply with international environmental norms and its commitment to preserving the constitutional integrity of its legal order.

Against this background, this Article uses the principle of autonomy as an analytical lens to understand how the EU legal order interacts with the obligations arising under the Aarhus Convention. Drawing on Kukovec’s conception of autonomy, it demonstrates that even where the term autonomy is not explicitly invoked, it provides the ‘omnipresent normative fabric of the Court’s decision-making and guides its legal argument’.[5] The Article also highlights the many facets of autonomy. Doctrinally, autonomy preserves the Court of Justice of the European Union’s (CJEU) exclusive jurisdiction to interpret EU law and limits access to the Court under the restrictive standing rules established in Plaumann;[6] politically, it guides the EU’s engagement in international fora and informs legislative strategies; and structurally, it shapes the boundaries between the internal coherence of EU law and the influence of external norms. Focusing on the Aarhus Convention highlights specific tensions brought on by autonomy in an area of shared competence, involving procedural rights. This focus also serves to demonstrate that autonomy in the field of environmental law is underexplored and how environmental law can serve as a testing ground for general principles of EU law. Because Aarhus obligations operate simultaneously at EU and Member State levels, they illuminate the complexity of mixed agreements and the tensions inherent in shared competences. For scholars of EU external relations, this offers a concrete example of how autonomy is operationalised in practice.

Ultimately, this Article argues that while safeguarding institutional autonomy and jurisdictional integrity is legitimate, an overly defensive approach risks undermining the EU’s credibility as a global actor committed to the rule of law and sustainable development. By focusing on environmental access to justice, the Article demonstrates how the EU seeks to balance respect for international legal commitments with the preservation of its legal autonomy, revealing autonomy not as a static shield, but as a flexible and contested interface between internal coherence and external accountability.

2.   The autonomy of EU law and the integration of international environmental law

The autonomy of EU law stems from the dual constitutional principles of supremacy and direct effect,[7] its origins identified in the seminal cases of Van Gend en Loos[8] and Costa v ENEL.[9] These cases established the foundations of the EU as a distinct legal order, capable to determine the effects of EU law, independently of national constitutional considerations.[10] Autonomy has since served to manage the interactions of the EU legal order, both with the legal orders of the Member States and with international law and external sources of law. In this respect, autonomy has been identified as having both an ‘internal’ and an ‘external’ manifestation, that is mirrored and adjusted depending on the legal order with which EU law interacts.[11]

The internal dimension is conceptualised as a mechanism for operationalising the integration of the EU polity,[12] by ensuring the uniform and consistent interpretation of EU law.[13] In relation to the administration of justice in particular, the autonomy of the EU legal order also shapes and delimits the procedural autonomy of the Member States. On the one hand, through the principle of effective judicial protection, developed initially as a general principle of law,[14] and later codified in Article 19(1) TEU and Article 47 of the Charter of Fundamental Rights. On the other hand, through the principle of effectiveness of EU law, originating from Rewe, to ensure that national procedural rules do not make it impossible or excessively difficult to exercise rights conferred by EU law.[15]

The external dimension of autonomy is conceived as a mechanism for protecting the EU legal order from interference from external legal orders,[16] and as a concept that ensures that the EU can determine its relationship with other legal orders.[17] While international agreements bind the EU under Article 216 (2) TFEU, their effects within the EU system are filtered through the CJEU’s interpretive authority, as emphasised in cases like Kadi.[18] The CJEU functions as a ‘gatekeeper’ of international law’s entry into the EU legal order, ensuring that the integration of international law respects the autonomy of EU law.[19] In this context, autonomy serves as a constitutional filter, enabling the EU to selectively internalise international legal norms in a way that safeguards the unity and uniformity of the EU legal order.[20]

The effects of international law are primarily determined through two judicial techniques. First, the CJEU may assess the legality of EU or Member State action on the basis of international agreements in cases where the relevant provision is deemed to have direct effect. This technique amounts to full incorporation, elevating the international rule to a standard of legality. Direct effect limits the discretion afforded to signatory parties under the agreement and can significantly challenge the autonomy of EU law. This concern is particularly evident in relation to provisions of the Aarhus Convention on access to justice, which, if directly effective, would constrain the procedural autonomy of the Member States and the EU in administering their judicial systems. Second, international law may be integrated by interpreting EU or national provisions in conformity with international obligations, in so far as possible. Consistent interpretation is considered as a more ‘subtle’ way of integrating international law,[21] but it is inherently qualified. It applies only where the legal provision allows for multiple interpretations and cannot lead to a contra legem interpretation.[22] Nonetheless, it offers a more flexible and less intrusive means for the integration of international law.

Overall, autonomy in EU law serves multiple functions. It safeguards the internal distribution of competences and the discretion of political institutions to shape the Union’s external relations[23] and secures the CJEU’s exclusive jurisdiction to interpret and review the legality of EU law.[24] As Eckes succinctly puts it, the overarching aim of autonomy is to ‘protect the monopolist position of the CJEU’ both over internal and external relations.[25] However, as the Article demonstrates, while autonomy enables the EU to integrate international obligations on its own terms, excessive insulation from international law risks undermining both the Union’s credibility and its commitment to the rule of law.

These tensions are distinctly illustrated by the EU’s engagement with the Aarhus Convention. Far from being a niche instrument of environmental law, the Aarhus Convention raises core questions about how the EU reconciles international obligations with its internal constitutional structure. Its provisions on access to justice sit at the intersection of environmental protection, fundamental procedural rights, and shared competences between the EU and the Member States. This makes the Aarhus Convention a natural testing ground for both the ‘internal’ and ‘external’ dimensions of autonomy: internally, it conditions the procedural autonomy of the Member States; externally, it tests how far the EU can absorb international commitments without ceding interpretive authority over its legal order. The case study therefore not only enriches the debate on autonomy in EU external relations but also broadens its relevance by showing how autonomy operates in a field with direct implications for citizens, NGOs, and the rule of law in practice.

3.   The Aarhus Convention and the EU: procedural autonomy at the intersection of legal orders

Building on Section 2, this section explores the legal complexity that the Aarhus Convention introduces into the EU’s internal legal order. This complexity has two pillars: first, it relates to the delimitation of procedural rights, impacting the contracting parties’ procedural autonomy, and second, it relates to the division of powers between the EU and the Member States in a shared competence field.

The Convention’s three pillars – access to information, public participation in decision-making, and access to justice – are designed to enhance transparency and accountability in environmental governance.[26] The Article focuses on Article 9(3) of the Convention, which establishes a general right of access to justice for the enforcement of environmental law. It requires each Party to ensure that, where individuals meet the relevant criteria under national law, they have access to administrative or judicial procedures to challenge acts or omissions by public authorities or private actors that breach national environmental law. Complementing this, Article 9(4) mandates that such procedures provide ‘adequate and effective remedies,’ including injunctive relief where appropriate, and that they be fair, equitable, timely, and not prohibitively expensive.

While Article 9(3) grants Parties discretion to determine the criteria for access to justice within their legal systems, this flexibility must be interpreted in light of the Convention’s overarching objective: ensuring broad and effective access to justice, particularly for members of the public and environmental NGOs. The Aarhus Convention Compliance Committee (ACCC), which oversees implementation of the Convention, and before which individuals, NGOs, Parties, and the Secretariat can raise compliance concerns,[27] has clarified that this discretion must not be exercised in a way that undermines the Convention’s purpose.

‘On the one hand, the Parties are not obliged to establish a system of popular action (actio popularis) in their national laws with the effect that anyone can challenge any decision, act or omission relating to the environment. On the other hand, the Parties may not take the clause ‘where they meet the criteria, if any, laid down in its national law’ as an excuse for introducing or maintaining so strict criteria that they effectively bar all or almost all environmental organizations from challenging acts or omissions that contravene national law relating to the environment.’[28]

Furthermore, the ACCC has read into Article 9(3) a presumption of access to justice, not allowing Parties to set too strict criteria that make it the exception,[29] thereby constraining the procedural autonomy of the parties. A similar interpretation has effectively been adopted by the CJEU and the EU Commission with regard to the Member States and their implementation of EU environmental law, as analysed below in Sections 4 and 5, but not by directly relying on the ACCC’s interpretation.

The Aarhus Convention has been signed and ratified both by the EU as a regional economic integration organisation (REIO) and the Member States on the basis of shared competences under the EU treaties,[30] and is considered a ‘mixed’ agreement under EU law.[31] To this effect, upon acceding to the Aarhus Convention, the EU adopted a declaration of competences, which pre-emptively sought to ensure its autonomy in relation to access to justice.

‘In particular, the European Community also declares that the legal instruments in force do not cover fully the implementation of the obligations resulting from article 9 (3) of the Convention as they relate to administrative and judicial procedures to challenge acts and omissions by private persons and public authorities other than the institutions of the European Community … and that, consequently, its member States are responsible for the performance of these obligations at the time of approval of the Convention by the European Community and will remain so unless and until the Community, in the exercise of its powers under the EC Treaty, adopts provisions of Community law covering the implementation of those obligations.’[32]

The EU’s complex constitutional arrangements that involve a dynamic division of competences with the Member States complicate the EU’s participation in such agreements. As will be analysed below in Section 5, the EU sought to use this declaration to limit the effect of ACCC findings against the EU.

The incorporation of the Aarhus Convention into the EU legal order has significant implications not only for the EU institutions but also for the Member States. It exemplifies how multi-level environmental governance operates in practice. As an integral part of EU law, the Convention falls within the interpretative jurisdiction of the CJEU,[33] whose preliminary rulings are binding on the Member States. Article 9(3) of the Convention grants discretion to contracting parties in determining the conditions for access to justice, which is typically reflected in national standing rules governing challenges to administrative action that contravenes environmental law. However, once incorporated into the EU legal framework, this discretion is further qualified on the basis of EU law.

4.   The CJEU’s engagement with the Aarhus Convention and ACCC Findings: navigating internal and external autonomy

4.1.  The impact of the Aarhus Convention on EU legal remedies

As this section reveals, the interpretation and legal effects of Article 9(3) of the Aarhus Convention diverge significantly in the CJEU’s case law, depending on whether access to justice concerns the EU or Member State level. This differentiation reflects the Court’s reliance on the principle of autonomy as a doctrinal safeguard, which conditions the reception and application of international norms within the EU legal framework, particularly in relation to the Union’s system of judicial remedies.

At the EU level, the requirements of Article 9(3) of the Aarhus Convention are partly determined by secondary legislation that enables internal review of administrative acts or omissions by EU institutions and bodies, and partly by constitutional law requirements regarding access to the CJEU both directly and indirectly. Access to justice in environmental matters is provided through three key avenues: a) direct access by non-privileged applicants to the CJEU under the annulment procedure of Article 263(4) TFEU; b) the preliminary reference procedure on the validity of EU legal acts under Article 267 TFEU, which is dependent on the discretion of national courts to refer to the CJEU; and c) the internal administrative review mechanism under the Aarhus Regulation.[34]

Access to justice in environmental matters at the EU level is significantly restricted. This is partly due to the narrow interpretation of standing requirements by the CJEU in annulment procedures under Article 263(4) TFEU, which has virtually excluded environmental NGOs, and partly due to the narrow scope of the internal administrative review procedure under the original Aarhus Regulation. As a result, in 2011, the ACCC provisionally noted that if EU courts continued with the same restrictive approach to standing, this would eventually lead to a breach of the Convention’s access to justice provisions, unless administrative review procedures compensated for that.[35] In its final findings in March 2017, the ACCC found that the post-Lisbon Article 263(4) TFEU, the internal review procedure under the Aarhus Regulation, and the CJEU’s case law did not bring the EU in compliance with Articles 9(3) and (4) of the Convention.[36]

As demonstrated below in Section 4.1, the impact of the Aarhus Convention and the aforementioned ACCC findings on the interpretation of Article 263(4) TFEU has been very limited, if any. Conversely, the impact on the preliminary references route, while indirect, has been extensive as evidenced in case law of the CJEU that expands access to national courts in environmental cases. Finally, as discussed below in Section 4.2, the impact of the Aarhus Convention on the Aarhus Regulation has been mixed; with limited effects on expanding its interpretation by the CJEU in the light of the Convention, but with significant effects of ACCC findings on legal reform which has expanded the scope of the Aarhus Regulation.

4.1.1. Direct access to the CJEU: limits of judicial engagement

Direct access to the CJEU is limited due to the restrictive interpretation of the requirements of direct and individual concern under Article 263(4) TFEU. Particularly, the well-known Plaumann interpretation of ‘individual concern’[37] has prevented access for groups of citizens and environmental NGOs, which would rarely, if ever, meet the standing requirements in order to challenge EU acts and omissions.[38] According to the case law applying the Plaumann test, individual concern may be established where applicants belong to a ‘closed group’ identifiable at the time of the measure’s adoption. However, due to the diffuse and generalised nature of environmental harm, environmental NGOs and affected individuals almost never meet this threshold.[39] As mentioned, together with the limited scope of the original Aarhus Regulation, the CJEU’s interpretation of ‘individual’ concern under Article 263(4) TFEU led the ACCC to conclude that the EU is not in compliance with its obligations on access to justice under the Convention.[40]

Nonetheless, the CJEU has consistently refused to broaden standing on the basis of the EU’s international obligations under Article 9(3) of the Aarhus Convention. It has denied direct effect to Article 9(3),[41] thereby precluding individuals or NGOs from relying on it to directly challenge the legality of EU acts. The Court has also ruled that Article 9(3) cannot override or influence the interpretation of Article 263(4) TFEU, since the Convention does not take precedence over the Treaties under Article 216(2) TFEU. [42] In the Court’s view, the standing requirements under the Plaumann test fall within the discretion afforded to parties by Article 9(3) to establish access criteria for judicial procedures.[43]

The Court has also confirmed its approach in the context of climate change litigation,[44] exhibiting a more restrictive stance, both as to the internal effects of the Aarhus Convention and the interpretation of standing of associations in climate cases, than the European Court of Human Rights (ECtHR).[45] The CJEU’s restrictive approach to standing has been the subject of considerable criticism in academic scholarship,[46] and there have been calls from within the CJEU for a more flexible interpretation.[47] Most recently, Advocate General (AG) Emiliou has called on the Court to refine the ‘closed group’ test, to allow for additional persons to be included in the group after the adoption of the measure, and to ensure that all applicants are treated equally, irrespective of the economic or non-economic nature of the interests they represent.[48] These suggestions could strengthen the role of associations,[49] including environmental NGOs. It is unclear whether the Court would follow the AG’s opinion and what impact it could have on access to the Court in environmental cases.

Following the ACCC findings against the EU in 2017, the European Commission clarified that it cannot instruct the CJEU on how to interpret Article 263(4) TFEU. Therefore, aligning EU access to justice obligations with the Aarhus Convention must occur through legislative reform, primarily via revision of the Aarhus Regulation, and by strengthening access to national courts.[50] The Commission placed particular emphasis on the preliminary reference procedure as an essential channel of access to justice, claiming this was insufficiently acknowledged by the ACCC.[51]

This position aligns with the CJEU’s holistic view of the EU system of judicial remedies, which encompasses both direct actions before the Court and indirect access through the preliminary reference mechanism. Under the principle set out in Foto-Frost, national courts are obliged to refer questions on the validity of EU acts to the CJEU,[52] rather than deciding on such validity themselves.[53] In this way, access to national courts may, at least in theory, reinforce access to justice at the EU level. This interaction places pressure on national courts to align their standing rules in environmental matters with the CJEU’s case law.

4.1.2. Access to national courts: expanding access through EU principles

Contrary to maintaining a restrictive approach to standing for direct actions at EU level, the CJEU requires that environmental NGOs be granted access to national courts to ensure effective protection of EU-derived rights, even outside areas where secondary legislation explicitly provides for access to justice. This divergence has produced a legally and normatively ‘unjustifiable’ double standard.[54] Although difficult to defend under the principle of effective judicial protection, this asymmetry can be understood as a reflection of how the CJEU operationalises the principle of autonomy within the EU legal order.

Unlike Articles 9(1) and 9(2) of the Aarhus Convention, which establish specific rights of access to justice in relation to access to information and public participation and have been implemented through EU secondary legislation, Article 9(3) has, to date, not been transposed through dedicated legislation.[55] In the absence of EU secondary legislation, the requirements of Article 9(3) have been fleshed out by ‘soft law’, namely a Commission Guidance,[56] through the inclusion of access to justice provisions in sectoral legislation,[57] and through the interpretation of Article 9(3) by the CJEU. Outside of areas of EU secondary legislation, the Member States maintain procedural autonomy in setting the rules for access to national courts, albeit subject to the principles of effectiveness and equivalence. The CJEU has used these principles to review the restrictiveness of national standing rules and to require national courts to open up their doors for challenges on environmental matters.

Slovak Brown Bears I provided the first opportunity for the CJEU to determine the scope of its jurisdiction to interpret Article 9(3) of the Aarhus Convention, as a provision of a mixed agreement that had partly been implemented in EU law.[58] While not explicitly mentioned, by asserting its jurisdiction to interpret Article 9(3), the CJEU safeguarded the autonomy of EU law in the sense of preserving the uniform and consistent interpretation of EU law as well as preserving the CJEU’s exclusive jurisdiction to interpret EU law. This is an approach that has been repeatedly followed in external relations cases.[59] In the case, a Slovak NGO challenged the way in which authorities were protecting the brown bear species under the Habitats Directive. AG Sharpston considered in detail whether the Court had jurisdiction to determine whether Article 9(3) of the Convention had direct effect. She emphasised the complexity of mixed agreements, referring to them as a ‘particularly contentious type of normative instrument in European law’[60] and ‘a creature of pragmatic forces – a means of resolving the problems posed by the need for international agreements in a multi-layered system’.[61]

In this context, the AG concluded that the Court has exclusive jurisdiction to evaluate the sharing of competences between the EU and the Member States, and in the context of mixed agreements, whether a particular issue falls within the competence assumed by the EU. This exclusivity safeguards the autonomy of the EU legal order, avoids legal uncertainty, and upholds the EU’s obligations as a contracting party.[62] Beyond that, however, the Court only had jurisdiction to interpret a provision of a mixed agreement that lies in a sphere in which the EU has legislated,[63] following Merck Genéricos.[64] According to the AG, ‘downstream’ legislation – in this case the Habitats Directive which governs the protection of the brown bear species – is not relevant for the purposes of determining whether Article 9(3) lies within the sphere ‘legislated by EU law’.[65] Taking into account such ‘downstream’ legislation would lead to a fragmented interpretative approach that would depend on the facts of a specific case.[66] Also, the AG was not able to establish the necessary link on the basis of EU environmental law more broadly.[67] The AG emphasised that the EU has not legislated so far in relation to Article 9(3). She also cited the Declaration issued by the EU upon signature of the Aarhus Convention,[68] to conclude that the obligations resulting under Article 9(3) remain within the competences of the Member States; they thus remain responsible for the performance of those obligations.[69]

Contrary to the AG, the CJEU took a broad and purposive approach in establishing its jurisdiction to determine whether Article 9(3) had direct effect despite the lack of its transposition in EU legislation as regards the Member States. It did so on the basis that the Aarhus Convention is a mixed agreement in an area of shared competence largely covered by EU law, and in light of the fact that the main proceedings concerned a dispute in relation to the Habitats Directive. Reiterating earlier case law on shared competences, the Court emphasised that ‘[w]here a provision can apply both to situations falling within the scope of national law and to situations falling within the scope of EU law, it is clearly in the interest of the latter that, in order to forestall future differences of interpretation, that provision should be interpreted uniformly, whatever the circumstances in which it is to apply…’.[70] The CJEU’s jurisdiction thereby rests on an autonomy rationale, which serves to safeguard the uniformity and effectiveness of EU law. Establishing its jurisdiction to interpret Article 9(3) is remarkable and has enabled the CJEU to develop clear obligations for national courts that restrict the discretion inherent in Article 9(3).

The CJEU held that Article 9(3) of the Aarhus Convention does not have direct effect in the EU legal order, as it lacks the necessary clarity and precision to directly regulate the legal position of individuals. Its implementation depends on national measures, since access to justice is granted only to those members of the public who meet criteria established by national law.[71] Nonetheless, invoking the principle of effectiveness of EU law, the Court stressed that Member States cannot exercise this discretion in a manner that renders it practically impossible or excessively difficult to exercise rights conferred by EU law. National courts are therefore required, particularly in areas governed by EU environmental law, to interpret national procedural rules as far as possible in line with the objectives of Article 9(3).[72] This reasoning rests on the combined application of the principles of effectiveness and effective judicial protection.

In this way, the CJEU sought to close the accountability gap by requiring broad access to justice for environmental NGOs at the national level,[73] albeit within the limits of consistent interpretation. Consistent interpretation mandates that national law be interpreted in conformity with EU (and international) obligations ‘so far as possible’, but does not extend to contra legem interpretation.[74] This raises the question: what happens when no such consistent interpretation is possible? The Court addressed this in Protect, a case referred by an Austrian court in 2017.[75] Again relying on the principles of effectiveness and effective judicial protection,[76] the CJEU held that when Member States establish procedural rules governing matters falling under Article 9(3), they act within the scope of EU law for the purposes of Article 51(1) of the Charter of Fundamental Rights. This was particularly relevant in situations where environmental NGOs seek to challenge administrative decisions potentially violating Article 4 of the Water Framework Directive (i.e., the non-deterioration obligation).[77] On this basis, the Court held that Article 47 of the Charter on the right to an effective remedy, read in conjunction with Article 9(3) of the Aarhus Convention, imposes an obligation on Member States to ensure effective judicial protection of rights stemming from EU environmental law.[78] While Article 9(3) affords discretion to national legislators, this discretion must not be exercised so restrictively as to prevent environmental organisations from contesting breaches of environmental law. [79] Otherwise, the effet utile of EU secondary legislation, such as the Water Framework Directive, would be seriously undermined.[80] Finally, reiterating the duty of national courts to interpret procedural rules in conformity with Article 9(3) and the principle of effective judicial protection so as to grant access to a duly established environmental NGO,[81] the CJEU made clear that, where consistent interpretation is not possible, the conflicting national provision must be disapplied.[82] Drawing on the principle of primacy as established in Simmenthal,[83] the Court confirmed that this obligation arises without the need for prior legislative amendment.[84]

While the lasting effects of the combined reading of Article 9(3) with Article 47 of the Charter of Fundamental Rights were initially unclear,[85] in Deutsche Umwelthilfe in 2022, the Grand Chamber reaffirmed the central reasoning of Protect. It confirmed that when a Member State lays down procedural rules governing matters falling within the scope of Article 9(3) of the Aarhus Convention, it is implementing EU law under Article 51(1) of the Charter and is therefore required to comply with Article 47 on the right to an effective remedy.[86] Adopting a functional interpretation of Article 9(3), the Court recognised that environmental NGOs must be entitled to challenge administrative decisions, such as the EC type-approval of vehicles,[87] considering that environmental NGOs have a right to challenge administrative decisions granting EC type-approval of vehicles, that may violate Article 5(2) of Regulation 715/2007, which prohibits the use of defeat devices which reduce the effectiveness of emission control systems.[88]

At the same time, the Court recalibrated its earlier position in Protect by limiting the obligation of national courts to disapply conflicting national rules to situations where the relevant provision of EU law has direct effect.[89] This adjustment aligns environmental access to justice case law with the general approach established in Popławski,[90] and followed in the CJEU’s case law since, including on judicial independence.[91] While this may limit the practical effects of supremacy as a conflict resolution rule, it avoids placing national courts in a legal dilemma where it is unclear which rule of law should prevail. This refinement is particularly significant in the Aarhus context. The Court clarified that because Article 9(3) does not have direct effect, it cannot, by itself, compel a national court to disapply a conflicting national provision.[92] Thus, the impact of Article 9(3) within the EU legal order is considerably reduced. However, the Court, reiterating previous case law,[93] held that Article 47 ‘is sufficient in itself and does not need to be made more specific by provisions of EU or national law in order to confer on individuals a right which they may rely on as such’.[94] Although not explicitly stated, this formulation is understood as confirming the direct effect of Article 47.[95] Accordingly, national courts are required to disapply national procedural rules that would prevent an environmental NGO from challenging a type-approval decision potentially violating Article 5(2) of Regulation 715/2007.[96] Notably, this obligation stems not from Article 9(3) of the Aarhus Convention, but from Article 47 of the Charter, further underscoring the limited influence of international law provisions that lack direct effect within the EU legal order. This shift also reflects a more rigid conception of the autonomy of EU law, where international norms lacking direct effect can only influence the internal legal order via mediating EU norms such as articles of the Charter of Fundamental Rights.

4.1.3. Interim findings: contrasting direct and indirect access to the CJEU

The CJEU’s case law on Article 9(3) of the Aarhus Convention and its impact on the Member States is driven by a willingness to enhance the enforcement of EU environmental law.[97] Its underlying rationale, as demonstrated below, relates to the limits imposed by EU law on the procedural autonomy of the Member States, through the operation of the principle of supremacy and effectiveness of EU law. Furthermore, the line of case law discussed above in Section 4.1.2 demonstrates how direct effect and consistent interpretation emerge as instruments for operationalizing autonomy, both internally and externally. They function as extensions of autonomy, translating the abstract principle into judicial techniques of integration and control.

Notably and consistently, when imposing obligations on the Member States, the CJEU is not directly or exclusively relying on the Aarhus Convention. It rather employs reasoning which stems primarily from the EU law principles of effectiveness and effective judicial protection, albeit inspired by the international convention’s requirements. If it relied on international law norms to demand wide access to justice from the Member States, it would have been equally required to abide by those international law considerations itself,[98] in light of the legal effects of international agreements in the EU legal order.[99] At the same time, reliance on Article 47 of the Charter to expand access to national courts for environmental organisations highlights an inconsistency; the CJEU does not apply the same logic when interpreting Article 263(4) TFEU regarding access to the EU courts. Since Article 47 of the Charter binds both the EU and its Member States, this asymmetry in access standards raises legitimate concerns about double standards in the EU’s system of judicial protection. Although the CJEU limits the effects of the Aarhus Convention on Article 263(4) TFEU on the basis of the hierarchy of legal sources in the EU, it is regrettable that it does not at least recognise the obligation to consistently interpret Article 263(4) TFEU in light of Article 9(3) of the Aarhus Convention. As AG Bobek noted, ‘what is required of the national courts must also be required of the EU Courts’, particularly in light of the fact that Article 263(4) TFEU, Article 47 of the Charter, and Article 9(3) of the Aarhus Convention constitute expressions of the principle of effective judicial protection, which is given a different meaning at the EU and at the national levels’.[100] Insisting on an autonomy rationale that preserves the independence of EU law and the Court’s exclusive jurisdiction to interpret EU law has led in this context to a distorted and selectively autonomous interpretation of effective judicial protection. Autonomy in this way shields the EU from the very standards demanded of Member States, thereby eroding the credibility and normative consistency of the Union’s commitment to the rule of law.

As demonstrated, the CJEU’s interpretation of Article 9(3) has been instrumental in strengthening Member State obligations, particularly by facilitating broader access to justice for environmental NGOs before national courts. In contrast, the EU level has seen no equivalent development. The constitutional sensitivity surrounding standing before the CJEU has thus shaped the extent to which Aarhus obligations are internalised at the EU level. Indeed, any progress in expanding access to justice within EU institutions has been driven less by internal legal evolution and more by sustained external pressure through the Aarhus Convention’s compliance mechanism.

4.2.  The CJEU and ACCC Findings: selective dialogue and doctrinal distance

The CJEU’s resistance to the Aarhus regime is further underscored by its consistent reluctance to explicitly engage with the findings of the ACCC, particularly in its case law concerning Article 9(3). The Court has refrained from directly addressing the ACCC’s findings, whether in assessing the EU’s own compliance with the Convention or as interpretative tools when construing the Convention or related secondary legislation. This approach illustrates the absence of any formal dialogue between the CJEU and the ACCC, with both bodies instead ‘operat[ing] autonomously in parallel’[101] in their interpretation of the Aarhus Convention.

Nonetheless, the CJEU does engage with the ACCC’s work, albeit indirectly and selectively.[102] On the one hand, the ACCC’s findings appear to have minimal impact on the Court’s interpretation of the EU’s compliance with access to justice obligations, as evidenced by its restrictive stance on Article 263(4) TFEU and, as discussed below in Section 5.2, in its interpretation of the Aarhus Regulation. On the other hand, there are instances of implicit influence. The Court has relied on the Aarhus Implementation Guide, a non-binding interpretative document endorsed by the ACCC, and has drawn on Advocate General opinions that increasingly cite ACCC findings.

The CJEU has yet to engage explicitly with ACCC findings on the interpretation of Article 9(3), even in contexts where such findings were not directed to the EU. In Slovak Brown Bear I and Protect, the Court reached conclusions largely aligned with the ACCC’s views on the scope of discretion under Article 9(3), but without citing the Committee’s findings or even the Implementation Guide, which had integrated them.[103] In contrast, both AG Sharpston in Protect,[104] and the Commission in its interpretative notice,[105] referred directly to the Implementation Guide. A more jurisprudentially open and internationally oriented approach could promote a level playing field in applying Article 9(3) uniformly across all contracting parties.[106] As already indicated above, the CJEU’s hesitation may stem from a strategic consideration: openly relying on international sources such as the ACCC could create pressure for the EU itself to meet the same standards. By grounding Member States’ obligations in EU principles, particularly effectiveness and supremacy, rather than in international law, the CJEU preserves a doctrinal distinction between the EU and its Member States regarding international commitments.

Interestingly, the Court shows more receptiveness to international law in interpreting other provisions of the Aarhus Convention, suggesting that policy context significantly shapes its approach. Still, the CJEU’s interaction with the ACCC remains confined to a ‘muted’ form of dialogue,[107] while the Court refers to the Implementation Guide[108] as ‘an explanatory document capable of being taken into consideration,’[109] its reliance is often indirect and mediated through AG Opinions, which themselves increasingly refer to ACCC findings.[110] This demonstrates a cautious openness to external oversight.

The CJEU’s selective engagement may partly be attributed to the non-binding legal nature of the ACCC’s findings. ACCC findings are not considered legally binding, given the nature of the ACCC as a ‘non-confrontational, non-judicial and consultative’ compliance mechanism.[111] Nonetheless, ACCC findings are usually endorsed by the Meeting of the Parties (MOP), and they are relevant ‘for compliance and implementation of the Convention’.[112] As such, they have been relied upon by national courts of contracting parties.[113] They offer the opportunity for dialogue between the treaty institutions and contracting parties with the ultimate objective of achieving compliance.[114] The ACCC’s non-judicial character arguably poses less of a threat to the CJEU’s institutional autonomy,[115] and thus could offer a more flexible avenue for engagement, particularly through the mechanism of consistent interpretation.[116] The Court’s reluctance to pursue even this limited form of alignment suggests a cautious, autonomy-preserving stance vis-à-vis international oversight mechanisms. This reserved stance likely reflects the CJEU’s broader concern with preserving the autonomy of the EU legal order, which is both self-referential and protective of the EU internal hierarchy of norms. Another possible explanation for the lack of explicit engagement is that the ACCC does not cite CJEU case law in its own findings, though this applies broadly to national case law of the contracting parties. However, lack of reciprocity cannot justify the CJEU’s silence. As the Court held in Venezuela v Council, the EU’s rule of law obligations ‘cannot in any way be made subject to a condition of reciprocity’ in relations with third countries.[117] Due to the formal incorporation of the Convention in the EU legal order and the ACCC’s recognised role as its interpretative body, the CJEU should refer to ACCC findings where applicable.

Ultimately, while a degree of autonomy is essential to ensure the CJEU’s legitimacy and coherence in legal reasoning, excessive isolation from international law may damage the EU’s credibility and weaken its commitment to the rule of law.[118] A more constructive engagement with interpretative bodies like the ACCC would contribute to a more integrated and principled development of EU law in line with the EU’s international commitments.

5.   Legislative responses to ACCC Findings: between compliance and control

The approach of the CJEU to international law is only part of the picture relating to compliance with the EU’s international obligations. The EU influences and shapes international developments and determines their effects in the EU system also by participating in international fora and adjusting its legislation. The EU legislative organs adopt an arguably more open and receptive approach to international law, compared to the Court.[119] This is done by adopting internal legislation on environmental matters, which often goes beyond what international agreements require or in situations when the EU is not bound by the relevant agreement.[120] At the same time, as this section demonstrates, autonomy serves to maintain the allocation of powers among EU institutions, thereby maintaining the institutional balance within the EU.

In the field of access to justice, the legislature’s openness is seen in the initial adoption of the Aarhus Regulation, which explicitly refers to provisions of the Aarhus Convention, and in the revision of its scope in 2021 and of state aid rules in 2025, both as responses to ACCC findings against the EU. This openness is also shown by the active participation of the EU in MOPs of the Aarhus Convention and overall willingness to adjust secondary legislation and ensure that EU remedies respond to the requirements of the Convention. Nonetheless, this openness is not unlimited; it reflects an autonomy-driven rationale, which sometimes qualifies the timing and extent of compliance with international obligations. In fact, the political organs of the EU often rely on the Court’s approach to autonomy, in preserving the special characteristics of the EU when conducting the EU’s external relations in the context of the Aarhus regime.

5.1.  Strategic engagement at the Aarhus MOP: participation, resistance and autonomy requests

Since the 2017 findings of the ACCC on the EU’s non-compliance with Articles 9(3) and 9(4) of the Convention, the European Commission has taken various steps, initially to qualify the findings, and subsequently to explore options for improving access to justice in environmental matters in the EU legal order, all while maintaining the EU’s institutional balance. Concerns about autonomy and the need to preserve the EU’s special features have led the EU to request ‘special treatment’ in the context of multilateral compliance mechanisms under international environmental agreements.[121] While maintaining its commitment to international cooperation, the EU’s insistence that compliance bodies should accommodate the internal complexity of its legal architecture, particularly the division of competences among EU institutions and between the EU and its Member States, reflects a reluctance to accept equal treatment in the assumption of international obligations.

In its comments to the provisional findings of the ACCC, the EU Commission requested a further hearing and asked the Committee to take into account the ‘specific nature’ of the EU legal order in providing access to justice before reaching its final findings.[122] It stressed the role of the CJEU in determining the internal legal effects of the Aarhus Convention. Characteristically, it stressed that an international agreement like the Aarhus Convention ‘cannot affect the allocation of powers fixed by the Treaties, or, consequently, the autonomy of the Union legal system’.[123] Additionally, the Council called for the parties to the Aarhus Convention to ‘take note of’ the findings, as opposed to endorsing them.[124] It also requested the removal of any references in the recommendations of the ACCC to the CJEU, citing grounds of separation of powers among EU institutions and its inability to give directions to the CJEU.[125] Given these requests, it was impossible for the parties to the Aarhus Convention to reach consensus on the adoption of the Decision ratifying the ACCC’s findings at the sixth Meeting of the Parties. ‘Taking note of’ ACCC findings, as the Council had suggested, would undermine the authority of the Meeting of the Parties and the compliance mechanism, as it would be unclear whether any legal or political consequences would follow. Instead, the parties deferred the decision to the next Meeting of the Parties in 2021.[126] In the meantime, the EU submitted progress reports on the Committee’s findings.[127] These moves by the Commission and the Council demonstrate how not only the Court, but also the EU political institutions seek to preserve the autonomy of the EU legal order and the exclusive jurisdiction of the Court.[128]

While ACCC findings, even when endorsed, may not be strictly legally binding as discussed above in Section 4.2, the EU has committed to international obligations under the Aarhus Convention and to comply with findings of the ACCC by becoming a party to the Convention. In contrast to the CJEU’s position, which avoids acknowledging any binding effect of the ACCC’s findings, the EU’s political institutions have repeatedly acted on the understanding that the Union is, in practice, bound by them. As indicated by the European Commission, after being endorsed by the MOP, ACCC findings ‘…gain the status of official interpretation of the Aarhus Convention and be binding on the Parties of the Aarhus Convention and the Aarhus Convention bodies’.[129] This approach is also reflected in the 2025 revisions on state aid rules discussed below in Section 5.3.

Nonetheless, the endorsement of ACCC findings against the EU at the Aarhus MOP has not been straightforward. MOP decisions are usually taken by consensus or exceptionally by three-fourths majority of the parties present and voting.[130] With 27 members out of 48, if all contracting parties are present, the EU and its Member States can effectively block the requisite majority. The political leverage of the EU in the Aarhus regime is thus significant and has been exercised in the context of ACCC findings to postpone their endorsement, at least until the EU figured out a way to comply. This was done both in relation to the ACCC findings against the EU in relation to ACCC/C/2008/32 on access to justice at EU level[131] and in relation to ACCC/C/2015/128 on access to justice in relation to state aid decisions, discussed further below.[132] The former were eventually endorsed at the MOP in 2021,[133] after the EU had revised the Aarhus Regulation, and the latter remain to be endorsed. Using political leverage in mixed agreements to postpone, delay, or undermine the incompatibility decisions against the EU can set a dangerous precedent, undermining the legal effects of international law and the EU’s commitment to it. It also shows how politically the EU institutions seek to preserve the autonomy of the EU legal order, by first identifying the most appropriate way by way of legislative reform to abide by the EU’s international obligations, before the official international endorsement of decisions finding the EU to be in breach of such obligations and containing specific recommendations for achieving compliance.

In June 2018, following significant political and social pressure, both from within[134] and outside the EU,[135] the Council of the EU requested the Commission to submit a study on the EU’s options to comply with the ACCC findings and to explore possible amendments to the Aarhus Regulation.[136] Consequently, in October 2019, the Commission published a detailed external study on the current situation on access to justice in environmental matters at the EU level.[137] It highlighted the complementary nature of the different judicial redress mechanisms in the EU legal order: direct access to the CJEU under Article 263(4) TFEU (which the Commission cannot interfere with), indirect access through national courts and preliminary references on validity under Article 267 TFEU, and the administrative review mechanism under the Aarhus Regulation. According to the Commission, not all three mechanisms need to be available for all different kinds of applicants, but rather effective judicial protection is to be ensured through the whole system of remedies.

In October 2020, alongside its proposal to amend the Aarhus Regulation, which is discussed below in Section 5.2, the European Commission issued a Communication on ‘Improving access to justice in environmental matters in the EU and its Member States.’[138] While ostensibly aimed at addressing the ACCC findings, the Communication reaffirms the structural autonomy of the EU legal order as the guiding framework for interpreting and implementing international obligations.

This Communication puts the proposal to revise the Aarhus Regulation in context, clarifying that the revision is done in a way that is compatible with the fundamental principles of the EU legal order and its system of judicial review, in accordance with the Budva Declaration.[139] Notably, the Communication emphasises the sui generis nature of the EU as an REIO and draws on CJEU case law to argue that the Aarhus Convention was primarily designed for national legal systems. It explicitly refers to a controversial passage from the General Court’s reasoning in ClientEarth v Commission,[140] endorsed by the Court of Justice on appeal,[141] by which it confirms that the Aarhus Convention was manifestly designed with national legal orders in mind and not the specific legal features of institutions of a regional economic organisation like the EU. This reasoning effectively distinguished the EU as a party to the Aarhus Convention in a way that was not necessarily intended at the international level, raising concerns as to the EU’s true commitment to international law and the rule of law. The Commission’s insistence on Member State responsibility under Article 4(3) TEU and Article 19(1) TEU signals a deliberate shift, also evident in the approach of the CJEU demonstrated above in Section 4.1.2: the burden of ensuring broad access to justice is transferred onto national legal systems.

This shift is done by highlighting the important role of the right to an effective remedy under Article 47 of the Charter.[142] The trend of using the principle of effective judicial protection and Article 47 of the Charter to boost the application of the Aarhus Convention in the Member States, established by the CJEU in Slovak Brown Bears[143] and Protect,[144] is thereby confirmed and continued by the Commission. While the Communication encourages Member States to strengthen access to justice through national transposition of EU secondary legislation and judicial remedies, its framing avoids reconfiguring standing rules at the EU level. Instead, it highlights national courts’ roles, including their capacity to refer questions to the CJEU under Article 267 TFEU, as complementary mechanisms. In effect, the Communication reflects a strategy of compliance through decentralisation, enabling the EU to respond to international legal criticism while safeguarding institutional autonomy. It illustrates how the Commission, like the CJEU, engages with external legal pressures by reinforcing the boundaries of the EU legal order and channelling compliance responsibilities to Member States, thereby maintaining internal coherence without formally relinquishing control. It is notable that following the Communication’s emphasis on including access to justice provisions in new sectoral legislation as a means to improve the effective implementation of EU environmental law, an increase in such provisions has been identified in contemporary environmental legislation of the EU. This approach has been criticised as presenting many pitfalls and creating ‘a patchwork of inconsistent approaches’.[145]

5.2.  Reforming the Aarhus Regulation: expansion and remaining gaps

The main mechanism for implementing Article 9(3) of the Aarhus Convention at EU level is provided in Article 10 of the Aarhus Regulation, enabling internal review of EU acts that may contravene environmental law. This procedure triggers social accountability, allowing primarily environmental NGOs to hold EU institutions to account. As Bogojević notes, the initial Regulation was not only restrictive ‘in defining who is entitled to review and what can be reviewed but, the impact of such a review is also narrow in scope.’[146] Overall, the 2021 amendment to the Aarhus Regulation has significantly expanded its scope and bears great potential for the internal administrative review mechanism to fill the gap of access to justice in environmental matters at EU level. It also shows the long and dynamic interaction between the EU legal order and the Aarhus Convention system,[147] as well as showcasing autonomy as the underlying rationale and driver for both legislative and judicial reactions to findings by the ACCC against the EU. Overall, the 2021 revision of the Aarhus Regulation must be understood as part of a re-balancing of the EU’s system of remedies, designed to mitigate the CJEU’s restrictive approach to Article 263(4) TFEU and to reduce the resulting risk of systemic non-compliance with Articles 9(3) and 9(4) of the Aarhus Convention. The amendments introduced by Regulation 2021/1767[148] address primarily the ‘what’ and the ‘who’, while the ‘impact’ largely remains the same.

The discussion that follows analyses the limits of the original scope of the Regulation, the Court’s approach in interpreting it in ways that limited the impact of the Aarhus Convention and maintained the EU’s autonomy, as well as the 2021 revisions introduced as a result of ACCC findings against the EU for failing to comply with Articles 9(3) and 9(4) of the Convention. It is notable, that the interaction between the EU legal order and the Aarhus regime has involved an open dialogue between the EU political institutions and the ACCC, in the form of progress reports submitted pending compliance and endorsement of the ACCC findings and in the EU seeking advice on the Commission’s proposal to amend the Aarhus Regulation, and subsequently amending the final revision to address contentious points identified by the ACCC in its advice.

5.2.1. Scope of administrative acts: expanding the ‘what’

The material scope of the initial administrative review procedure was restricted to administrative acts, meaning ‘any measure of individual scope under environmental law,… and having legally binding and external effects’,[149] which limited the mechanism considerably. In practice, since the entry into force of the Aarhus Regulation, concerning requests lodged with the Commission from June 2007 to December 2020, around 80% were found inadmissible, in whole or in part.[150] Of these, more than half were found inadmissible due to the fact that the act was not of individual scope. The interpretation of measures of individual scope excludes acts addressed to the Member States, which do not themselves impose obligations on specific operators, such as Commission acts authorizing derogations from the Air Quality Directive and acts amending the maximum residue levels for pesticides.[151] The ACCC had highlighted that while Article 9(3) leaves discretion to signatory parties to set conditions for access to justice at the national level, this does not leave discretion as ‘to acts that may be exempted by implementing laws’.[152]

The CJEU had numerous occasions to expand the interpretation of the scope of acts covered by Article 10 of the Aarhus Regulation. However, it limited the effects of the Aarhus Convention. Given the lack of direct effect of Article 9(3), the cases focused on whether limiting the internal review mechanism to administrative acts of individual scope could be reviewed by the Court through alternative means.[153] Firstly, attempts were made to broader review of the Regulation through the implementation principle. The principle was developed in relation to World Trade Organization (WTO) agreements, which do not have direct effect. According to this principle, it is possible to review the legality of EU law on the basis of international agreements which do not have direct effect when the EU act at issue explicitly refers to provisions of the agreements or intends to implement a particular obligation of the EU under the international agreement. The ECJ, reversing the decisions of the General Court, limited the implementation principle considerably, holding that ‘those exceptions were justified solely by the particularities of the agreements that led to their adoption’.[154] Unlike the case law concerning WTO law, the ECJ considered that Article 10 of the Aarhus Regulation does not explicitly refer to Article 9(3), which itself does not confer rights on individuals to invoke international provisions.[155] This approach is problematic, given that the Aarhus Regulation makes multiple references to the Aarhus Convention.[156] Requiring a specific reference to the international agreement in the provision in question is overly restrictive.[157] Also, the Aarhus Regulation was found not to implement a ‘specific’ obligation as found in the case law relating to WTO agreements.[158] According to the Court, Article 9(3) of the Aarhus Convention grants a broad margin of discretion to parties to determine the conditions of administrative and judicial procedures.[159] Although WTO law is very different from environmental issues, ‘the sharp dichotomy between both policy spheres does not appear wholly justified’ in limiting the effects of different international agreements.[160]

Notably, in these cases the ECJ rejected the implementation principle on the basis of internal considerations, relating to the division of competences between the EU and the Member States, rather than international norms. According to the ECJ, the Convention’s obligations on access to justice fall primarily within the scope of national law.[161] The Court thereby shifts the responsibility of honouring international obligations to the Member States[162] and to the EU political organs, effectively urging them to amend the Aarhus Regulation if they wish to expand this administrative mechanism. External autonomy from international law thereby reinforces internal autonomy from the Member States.

Secondly, attempts were made to broaden the Aarhus Regulation through consistent interpretation. In Mellifera, the CJEU held that it was not possible to interpret the scope of the Aarhus Regulation consistently with Article 9(3), which does not allow parties to limit access to justice to particular kinds of acts, in order to expand the administrative review procedure established by Article 10.[163] This would amount to a contra legem interpretation, given the clear definition of administrative acts under the Regulation, which limits the scope of the review procedure to acts of individual scope.[164] In this case, the Commission Implementing Regulation extending the approval period of the active substance ‘glyphosate’ was considered an act of general scope that could not form the subject of a request for internal review. It did not amount to a marketing authorization by a specific applicant but rather regulated the approval processes of plant protection products with that substance by Member State authorities. Notably, the Court did not explicitly and meaningfully engage with the ACCC findings on the Aarhus Regulation, highlighting that the caveat of Article 9(3), which allows for criteria to be imposed: it does not leave discretion as ‘to acts that may be exempted by implementing laws’. The CJEU is reluctant to rely on interpretations offered by the ACCC as the review body tasked with overseeing compliance with the agreement. This serves to preserve the EU political institutions’ discretion to determine the best way to comply. It also safeguards the autonomy of the EU legal order (both in a legal and political sense). At the same time, however, it raises questions as to the EU’s strict observance of international law.

Following the 2017 ACCC findings,[165] the CJEU was faced with the opportunity to revisit the interpretation of ‘administrative acts’ under the Aarhus Regulation. In this context, the General Court rejected the applicants’ claim that a narrow interpretation of administrative acts was incompatible and no longer permitted following the ACCC findings. Specifically, the General Court clarified that,

‘[i]n any event, assuming that those recommendations are binding on the Contracting Parties to the Aarhus Convention, they are, as the Commission rightly observed, only a draft and, … that draft was not adopted by that committee until 17 March 2017, which was after the date on which the contested decision was adopted. It is not necessary therefore to answer the question whether, as the Commission maintains, making reference to the Aarhus Convention Implementation Guide, the recommendations of the Aarhus Convention Compliance Committee were to be adopted by the meeting of the Parties, provided for in Article 10 of the Aarhus Convention, or whether that was not necessary, as the applicant maintains’.[166]

The General Court thereby avoided determining the legal status of ACCC findings and any obligations on the CJEU to rely on such findings, even after the date of their official adoption by the ACCC or even after their eventual endorsement by the Meeting of the Parties. The above paragraph represents the only explicit reference by the General Court to ACCC findings to date. On appeal, regrettably, the ECJ neither mentioned the ACCC findings nor commented on the applicants’ allegations that the General Court wrongly held that the ACCC findings could not influence the interpretation of the Aarhus Regulation,[167] confirming its consistent reluctance to directly rely on ACCC findings.[168] The ECJ instead focused on the interpretation of administrative acts of individual scope and reiterated that the Aarhus Regulation is in conformity with the Convention, considering the discretion left to signatory parties under Article 9(3). This approach reinforces the implicit usage of autonomy, both in the sense of the CJEU’s exclusive jurisdiction to interpret EU law and in the sense of self-reference, as the underlying logic for limiting the effects of international agreements and decisions of international review bodies in the EU.

The CJEU thereby demonstrated the limits of consistent interpretation, deferring to the legislature to expand the scope of the Aarhus Regulation if desired, demonstrating how autonomy serves to preserve political discretion to conduct the EU’s external relations. The boundaries of consistent interpretation contribute to shaping not only the EU’s relations with external regimes but also the CJEU’s relations with other EU institutions. Given the limits of judicial interpretation together with the pressure created by the ACCC findings on the EU’s compliance with Articles 9(3) and 9(4) of the Convention,[169] the European Commission proposed amendments to the Aarhus Regulation in October 2020. The amendments surpass the limits of consistent interpretation and expand the kinds of acts that can form the subject of internal review to acts of general scope, including acts adopted on the basis of non-environmental legal bases and pursuing non-environmental objectives.[170]

The Amending Regulation has expanded the material scope of the review procedure by amending the definition of ‘administrative acts’ under Article 2(1)(g) of the Regulation in three ways.[171] First, it broadens the scope beyond administrative acts of ‘individual scope’ (i.e., acts which either directly address a person or where the person affected can be distinguished individually) to non-legislative of ‘general scope’ with legal and external effects. This is an important and welcome amendment, given that the previous narrow scope was identified as a key obstacle by NGOs, enabling the Commission to reject most requests for internal review. The amended definition would cover acts of general scope, such as the implementing regulation approving the active substance glyphosate, which was considered an act of general scope by the CJEU in Mellifera. Notably, the scope is broader than the initial proposal of the Commission, which would limit it to acts not explicitly entailing implementing measures at Union or national level.[172] This new exception, as initially proposed by the Commission, was heavily criticised in the advice provided by the ACCC on the proposal,[173] and would have significantly restricted the scope and effectiveness of the internal review mechanism.[174] Second, the material scope of the internal review mechanism has been extended beyond acts adopted ‘under environmental law’, to acts and omissions contravening environmental law, irrespective of the objectives of the specific act. In other words, acts adopted under non-environmental competences and pursuing primarily other objectives, which contravene environmental law (broadly defined) would fall within the scope of the Regulation. Third, the mechanism now covers acts which have legal (not legally binding) and external effects. (Article 2(1)(g)),[175] while non-binding acts continue to remain outside of the scope of the Regulation.

The importance of expanding the material scope of the Regulation in these ways is demonstrated by ClientEarth v European Investment Bank (EIB).[176] Even though the judgment concerns the interpretation of the Aarhus Regulation before its revision in 2021, it is likely that the reasoning has been implicitly influenced by the subsequent broadening of the Regulation. The case concerned a request for internal review of a decision by the EIB to fund the construction of a biomass power general plant in Spain. In line with the Aarhus Convention and its objective to ensure wide access to justice in environmental matters, both the General Court and the ECJ adopted a broad interpretation of the requirement for an act to be adopted ‘under environmental law’ in accordance with the Aarhus Regulation.[177] The Aarhus Regulation covers acts which can infringe environmental law and thereby contribute to the pursuit of the objectives of Article 191(1) TFEU.[178] In this context, the EIB’s Climate Strategy and the Statement of Environmental and Social Principles and Standards, requiring the EIB to take into account environmental criteria in determining the eligibility of projects, rendered the decision one taken under environmental law.[179] In this context, the Court indicated that, when taking lending decisions, the EIB cannot, without justification, depart from the environmental criteria it set for itself in the climate strategy and the 2009 statement of environmental and social principles.[180] It held that the EIB was precluded from unjustifiably departing from or ignoring these criteria without risking violating the principle of equal treatment or the protection of legitimate expectations.

The Court’s teleological approach also reflects the clarifications in the 2021 revision on the scope of the Aarhus Regulation, which covers acts adopted in the implementation of other (non-environmental) policies, which should be subject to internal reviews to consider whether they could have an adverse effect on the objectives of Article 191 TFEU. The timing of this decision is important given that it reflected the amendments proposed by the European Commission, and at the time endorsed by the Council, for administrative acts under the Aarhus Regulation not to be limited to those taken ‘under environmental law’. The CJEU’s approach is thus reactive and may be explained by its effort to maintain the allocation of powers within the EU and respect legislative intentions.

As to the ‘legally binding and external effects’ criterion for determining whether the resolution could be considered a reviewable act, the Court held that the resolution reflected the EIB’s definitive position on the eligibility of the specific project for the grant of financing. The CJEU clarified that even though this decision did not create a legal obligation for the EIB to fund the project, it altered the legal position of the project’s promoter in a definitive manner by enabling them to proceed to the next steps towards finalising the loan.[181] Again, the timing of the judgment, following the revision of the Aarhus Regulation, which now extends to acts with legal (and not legally binding) and external effects, may have influenced the Court’s approach.

Despite the significant changes, the revision of the Aarhus Regulation fails to address certain problematic aspects of the Regulation that were highlighted in the ACCC findings. For instance, it does not extend the scope of administrative acts to acts with no legally binding or external effects. The Commission’s justification for this is not entirely convincing. On the one hand, the Commission highlights that this is consistent with the CJEU’s interpretation of ‘reviewable act’ under Article 263(1) TFEU and given that the internal review procedure under the Aarhus Regulation is supplementary to direct access to the CJEU, such an expansion is unnecessary. On the other hand, it justifies this approach on the basis that only legally binding acts are capable of contravening environmental law. This is, however, contrary to the ACCC findings, which reiterated that just as the parties do not have discretion to limit access to justice under Article 9(3) to acts of individual scope, they do not have discretion to restrict access to justice to acts that do not have legally binding and external effects. Also, non-legally binding EU acts can have significant effects both on the implementation of EU legislation and its interpretation by the CJEU. In that sense, for example, post-legislative Commission guidance, on the basis of which the Commission implements secondary legislation, could possibly contravene environmental law, as can guidelines on state aid for environmental protection and energy. Also, acts that the Commission considers have no external effects, such as the adoption of a list of proposed candidates to the Management Board of the European Chemicals Agency for the position of Executive Director of the Agency, may have impacts on the environment. Such instances were highlighted by ClientEarth, as the communicant of the ACCC complaint against the EU, as examples where the Commission unjustifiably rejected requests for internal review, contrary to the requirements of Article 9(3) of the Convention.[182] The ACCC in its advice to the Commission on the proposal to amend the Aarhus Regulation, indicated that this restriction limited the scope of review unjustifiably, as there is no legal basis in the Convention to limit the scope to acts with ‘binding’ legal effects.

5.2.2. Expanding the circle: ‘who’ can request a review

The personal scope of the Aarhus Regulation review mechanism has also been significantly expanded in the 2021 revision. Other members of the public that meet specific conditions and are represented either by an environmental NGO or a lawyer can make a request in two instances. This is a significant step forward. It was incorporated in the revision following an initial assessment and advice by the ACCC, which indicated that extending the personal scope beyond environmental NGOs to other members of the public was necessary to ensure compliance with the Aarhus Convention.[183] The first instance under Article 11(1)(a) is determined by qualitative criteria[184] and requires an impairment of rights and being directly affected by such impairment in comparison with the public at large. This does not require that they are directly and individually concerned within the meaning of Article 263(4) TFEU, but they should demonstrate that they are directly affected in comparison to the public at large, for example in the case of an imminent threat to their own health and safety, or of prejudice caused to a right they are entitled to under EU law.[185] The second instance under Article 11(1)(b) requires a sufficient public interest and for the request to be supported by at least 4 000 members of the public residing or established in at least five Member States, with at least 250 members of the public coming from each of those Member States. It combines qualitative and quantitative criteria.[186] Sufficient public interest in protecting the environment, human health, the rational utilisation of natural resources or combating climate change has to be proven collectively, given that the request has to come from a minimum number of members of the public from a minimum number of Member States. This is inspired by the European citizens’ initiative and resembles a public petition given that there is no requirement for the public interest to be violated. It has to exist and be sufficient.

Despite the broadened scope, the reforms of the Regulation do not appear to be fully in line with the Findings of the ACCC and the requirements of the Aarhus Convention itself. Specifically, Article 11(1)(a), as analysed above, with the conditions it introduces; firstly regarding the ‘impairment of the rights’ of the public and its direct effect by the regulatory act, and secondly regarding the minimum quantitative number of members that must support the public, according to Article 11(1)(b), are not consistent with the spirit of the Convention on establishing wide access to justice in environmental matters.[187] The broadened personal scope (beyond environmental NGOs) applies from April 2023, to allow time for the administration to adapt to the broadened scope, while in the meantime the violation of the Aarhus Convention requirements effectively persisted.

5.2.3. Review and remedy: the limits of impact

The impact of the internal administrative review mechanism partly depends on the standard of review exercised by the institution reviewing the act. The structure of the review mechanism raises concerns as to the impartiality, adequacy and fairness required by Article 9(4) of the Aarhus Convention. The institution that adopted an act is both unlikely to want to accept such requests and to revisit its decision-making.[188] Despite its narrow material scope, the Aarhus Regulation has enabled requests for internal review of some measures of individual scope, such as the authorization of placing on the market of genetically modified products, authorizations of chemicals under the REACH regime, and authorizations of monitoring organisations under the Timber Regulation.[189] However, even the nine requests deemed admissible by the Commission were found not to violate environmental law, usually on the basis of a brief statement on why the Commission disagrees with the interpretation of environmental legislation suggested by the NGO that lodged the request. In fact, none of the requests lodged with the Commission have led to an act being revised or withdrawn. This limited impact of the mechanism is likely to be maintained after the 2021 revisions of the Aarhus Regulation and is likely to arise in relation to the mechanism introduced in 2025 for state aid decisions, discussed below. The practical application of the internal administrative review mechanism also demonstrates the inherent limitations of such procedures to ensure wide access to justice.

Furthermore, the impact of the Aarhus Regulation mechanism on access to justice depends on the scope of the subsequent right to judicial review before the CJEU. Article 12 provides the possibility for NGOs that make requests for internal review under Article 10 of the Aarhus Regulation to challenge this process before EU courts. The ACCC had clarified that although the scope of this judicial review had not been interpreted by the CJEU at the time, it should extend to the substance of the initial administrative act for which an administrative review procedure had been sought. An interpretation that would limit judicial review to the written reply under the Article 10 procedure would be contrary to the requirements of the Convention. In the meantime, both the General Court and the ECJ in TestBiotech endorsed a restrictive interpretation of Article 12, not extending to a review of the initial act.[190] A successful application under Article 12 cannot lead to the annulment of the initial act, but only of the written reply to the request under Article 10, and the standard of review applied by the court is very demanding, examining whether the relevant institution committed a manifest error of assessment in its reply to the request for internal review.

This effectively means that NGOs wishing to challenge the legality of the initial act can only use the annulment procedure for acts not addressed to them under Article 263(4) TFEU, according to which they are unlikely to have standing. The General Court in ClientEarth v Commission,[191] indicated that when reviewing the procedure of the internal administrative review, the substantive reasons for challenging the initial act may be reviewed to the extent that they were relevant for the internal review procedure. However, as the ECJ clarified in Testbiotech, no new grounds may be raised as to the review of the initial act.[192] This is not sufficient to guarantee wide access to justice to challenge violations of environmental law as required by the Convention and to counteract the very restrictive scope for access to the CJEU by environmental NGOs under Article 263(4) TFEU.

In Testbiotech, when interpreting the scope of judicial review of the administrative review procedure under Article 12 of the Aarhus Regulation, the CJEU did not refer to the ACCC findings. The ACCC had indicated that an Aarhus-friendly interpretation, which would enable the review of the substance of the administrative act and not merely of the written reply to the request for an internal review, was required to be in line with the Convention.156 Coming to the opposite conclusion, and although no explicit reference was made to the ACCC findings,‘… the Grand Chamber must have certainly been aware of the fact that its reserved approach … might further the ongoing non-compliance at EU level with the access to justice requirements’.157 This approach reflects the limits of compliance with international law to prioritise autonomy.

These limits remain the same following the legislative reform. The material scope of judicial review is largely unchanged in the 2021 revision, apart from a recital in the preamble clarifying that it covers both the procedural and substantive legality of the written reply.[193] Also, who may have access to Article 12 will necessarily change in light of the expansion of the personal scope of Article 10 of the Regulation.

Overall, the amendments came into force in October 2021, while the amendment regarding the public’s right to request a review came into force in April 2023, and no such request has been received by the Commission yet. Therefore, whether the expanded scope of the Regulation will be sufficient to fill the gap and ensure substantial compliance with the Aarhus Convention remains to be seen in practice. The long-awaited amendment of the Regulation has significantly improved the provisions concerning public access to justice,[194] and its implementation has already demonstrated significant potential. Firstly, a significant increase in requests for internal review has been observed, particularly towards the European Commission, given that acts of general application can now also be reviewed. Before the revision, 48 requests had been lodged with the Commission since the entry into force of the Regulation in 2007. After the revision, from December 2021 to July 2025, the Commission has logged 69 requests, demonstrating an important increase in requests, now that generally applicable acts are reviewable. Comparatively with pre-revision requests, a larger number of requests are considered unfounded on substance rather than deemed inadmissible, leading to an overall balance between unfounded and inadmissible requests.[195]

A key example that highlights the importance of the Regulation’s expanded scope is the inclusion of the Union lists of projects of common interest (key cross-border energy infrastructure for building a more integrated and resilient internal energy market in the EU and achieving energy and climate targets). Requests for review of the fourth list had been deemed outside the original scope of the administrative review mechanism.[196] From the fifth list published in November 2021 onwards, these lists can now be subject to review requests. Additionally, review requests have been submitted to the Council, which has now created a public register of the applications it receives. Examples of received requests concern recurring decisions subject to annual review, such as the Council regulations setting fishing opportunities (or ‘total allowable catches’) within the framework of the Common Fisheries Policy.[197]

More broadly, during the implementation of the revised Regulation, due to the expanded scope, the focus has shifted from admissibility to the substance and judicial review of the requests based on Article 12. Applicants often argue that the institution violated environmental law provisions by ignoring relevant scientific evidence, even though the act should have been based on credible (or best available) scientific data, the precautionary principle, or the sustainability of plans, projects, or resource management. A characteristic example is the review requests[198] regarding the Commission’s classification of energy from forest biomass as ‘sustainable’ under the EU Sustainable Finance Regulation.[199] For this purpose, the Commission relied on the classification of forest biomass as a ‘renewable energy source’ under Union law.[200] According to environmental organisations that submitted the requests, the Commission did not take into account more recent data showing high levels of greenhouse gas emissions caused by burning forest biomass. The organisations have proceeded with a related legal action, challenging the Commission’s cursory response.[201] The case law of the CJEU consistently states that EU institutions have wide discretion when assessing complex scientific data, and that judicial review is limited to examining whether the institution made a manifest error of assessment and exceeded the limits of its discretion. In its response to the request, the Commission emphasised this discretionary power. It remains to be seen how the General Court will assess whether the decisions suffer from manifest errors of assessment in this context.

5.3.  Access to justice in state aid: the next frontier

Following the 2021 revision of the Aarhus Regulation, the material scope of the internal review mechanism was still limited, particularly given that competition matters are explicitly excluded from the scope of the regulation.[202] This includes state aid decisions which may contravene environmental law. State aid decisions are powerful instruments that affect the environment. For example, State aid decisions shape the EU’s energy market, affecting support to fossil fuels, to renewable energy sources, to nuclear energy, security of supply measures, which has a direct impact on the balance between polluting and non-polluting industries on the market. They can determine when an industry can benefit from free emissions (ETS) allowances or be compensated for indirect emissions costs. State aid decisions already have to comply with EU environmental law,[203] and in light of the principle of legality and the requirements of Article 9(3) of the Aarhus Convention, NGOs should be able to challenge this compatibility at EU level where the Commission and the CJEU are competent to determine whether national state aid decisions are compatible with internal market rules.

The exclusion of State aid decisions has no basis in the Aarhus Convention, which only excludes acts adopted by public authorities acting in their legislative or judicial capacities.[204] In March 2021, the ACCC found the EU in breach of the Aarhus Convention for failing to provide access to justice to environmental NGOs and citizens against the Commission’s State aid decisions breaching environmental law, and recommended that EU law must change.[205] In particular, the ACCC held that the EU failed to comply with Articles 9(3) and 9(4) of the Convention because of the lack of standing for an environmental NGO to challenge a state aid decision of the Commission in relation to the nuclear facility at Hinckley Point in the UK. With pressure from the EU, the MOP to the Aarhus Convention in October 2021 postponed the possible endorsement of the findings to the next meeting in 2025 (effectively until the EU figures out how to comply).

The EU, in its replies to the ACCC, emphasised the EU Declaration made upon signature and approval of the Convention,[206] and the requirement to take into account its institutional and legal context. It indicated the hierarchy of legal sources in the EU, highlighting provisions of the Treaties governing the state aid regime and the Commission’s exclusive competence to assess the compatibility with internal market rules, and which ‘rank[s] higher’ than that of the Convention. Notably, the EU requested the ACCC to ‘treat the EU differently from other Parties in so far as its specific institutional and legal context is concerned’. Along the same lines, the EU relied on case law of the CJEU as evidence that the Convention needs to be interpreted differently, taking into account the specific features of the Union, given that the Convention was ‘manifestly designed with the national legal orders in mind, and not the specific legal features of institutions of regional economic integration, such as the European Union’.[207] This emphasis on the specific/special/unique features of the EU reflects the principle of autonomy, which, from the perspective of the EU, separates the EU from other contracting parties in international agreements and in this instance seems to go as far as requiring the ACCC to follow the CJEU’s case law in its interpretation of the EU Declaration and of the provisions of the Aarhus Convention.

In response, the ACCC reiterated earlier findings on the effects of the EU’s Declaration by clarifying that the EU ‘assumes obligations to the extent that it has European Union law in force; Member States remain responsible for the implementation of obligations that are not covered by European Union law in force.’[208] It is therefore treated as a statement to take into account the division of competences between the EU and its member states and to determine the level (EU or Member State) at which the act being challenged was effectively adopted. Furthermore, the ACCC reiterated the shortcomings of available remedies in the EU legal order identified by the ACCC in ACCC/C/2008/32 (Part I) and ACCC/C/2008/32 (Part II), including the inherent limitations of the preliminary ruling procedure and the restricted scope of Article 263(4) TFEU as currently interpreted by the CJEU.[209]

The EU influenced the Parties to the Convention to postpone the official endorsement of the Committee’s findings against the EU until the next MOP in 2025, essentially allowing time for the EU to explore alternative means of compliance. [210] This interference by the EU, reflecting its previous practice in relation to ACCC findings against the EU, is considered arbitrary and worrying in terms of undermining the effects of an international review body, tasked to interpret and ensure compliance with an international agreement,[211] calling into question the EU’s commitment to the international rule of law.

On 17 May 2023, following public consultation, the Commission issued a Communication which stresses that ‘ensuring compliance with the ACCC findings in case ACCC/C/2015/128 requires an adjustment to the existing legal framework or equivalent measure’.[212] The Communication crystallised two key objectives: ensure compliance with the Aarhus Convention and preserve specificities of state aid control and its effectiveness, as one of the tools that can speed up the green transition. The challenge lay in how to find balance between the two. Eventually, to ensure EU compliance with the ACCC findings and to expand access to justice in relation to state aid decisions, and following public consultation, the European Commission proposed amendments to the rules on state aid, not to the Aarhus Regulation,[213] which had initially been considered as a possibility. [214] These proposals led, in May 2025, to the amendment of Regulation 794/2004[215] and the Code of Best Practices for the conduct of procedures concerning state aid control. [216] As put aptly by Delarue, these rules ‘bring some closure to a seven-year-long, politically laborious process of bringing EU law in line with international law.’[217]

According to the Best Practices Code (BPC), the amendments establish a new mechanism enabling environmental NGOs, under certain conditions, to request internal review of final decisions on state aid that may violate Union environmental law. Notably, NGOs must specify in their review request the specific provisions of EU environmental law that they claim the state aid violates.[218] The request must also be accompanied by specific information and factual circumstances supporting the claim.[219] As indicated in the Implementing Regulation, the NGOs will have to demonstrate that the aided activity or any aspect of the State aid measure approved by the Commission decision, which is ‘indissolubly linked’ to the goal of the aid, breaches environmental law. This criterion has been established in case law of the CJEU,[220] but has not been systematically defined. The Commission has indicated that it will issue guidance on this concept.

The material scope of the internal review request is limited to final decisions on state aid by which the formal investigation procedure, initiated under Article 108(2) TFEU, is concluded, and the aid is deemed compatible with the internal market. Review can be requested for all compatibility grounds under the TFEU for state aid approval, except in the case of social aid and aid intended to compensate for damage caused by natural disasters (Articles 107(2)(a) and 107(2)(b) TFEU). [221] The scope of the new internal review mechanism is thus inherently limited, excluding the large majority of state aid decisions – i.e., decisions not to raise objections. As the Commission indicated, the kinds of decisions covered by the new mechanism range from 12-18 per year,[222] and it is unclear if they will raise any potential violations of environmental law.

According to the BPC, for an NGO to be eligible to submit a review request, it must be independent and non-profit, with the primary statutory purpose of promoting environmental protection under environmental law. It must have existed for more than two years with that same purpose, and the reason for the review request must clearly fall within its statutory objectives.[223] Interested NGOs must substantiate that they meet these requirements by submitting supporting documents such as their statutes and annual activity reports.[224] NGOs must submit their request within eight weeks after the Commission State aid decision has been published in the official journal. The Commission then has up to 22 weeks to issue its reply. As indicated in the BCP, the NGO that made the request can institute proceedings before the CJEU, which will not have a suspensive effect on the state aid decision. The effectiveness of the new mechanism will largely depend on the standard of review exercised by the CJEU.

The impact of the Aarhus regime on the EU legal order is particularly evident in the repeated acknowledgement of the need to amend legislation in response to international commitments and the findings of the ACCC. This recognition is explicitly reflected in the title of the Implementing Regulation, in its preamble, which notes the ACCC’s conclusion that the EU was in breach of its obligations and urges corrective action through the establishment of an internal review mechanism, as well as in Annex IV of the Regulation, titled ‘Form for the submission of internal review requests following the ACCC findings in case ACCC/C/2015/128.’ Similar acknowledgments also appear in multiple references within Section 11 of the Code of Best Practices. Taken together, these measures indicate that both the EU legislature and the Commission, as the EU’s executive, attribute legal significance to the ACCC’s findings, recognising a duty to adapt the Union’s review mechanisms accordingly. This engagement demonstrates that, while autonomy remains a central principle of the EU legal order, it is not absolute.

Currently, the ACCC is expected to examine and determine whether this mechanism addresses the gaps identified in its findings.[225] The fact that the detailed criteria and procedure of the review mechanism, including the right to initiate proceedings before the CJEU, are set out in the BPC, which is a non-legally binding instrument, may raise questions as to whether the amendments are sufficient to ensure compatibility with the Convention’s requirements.[226] It also remains to be seen if the system will be effective and not create insuperable procedural and evidentiary hurdles for environmental NGOs.[227] In any case, in the upcoming MOP of the Aarhus Convention in November 2025, it is crucial for the ACCC findings against the EU on state aid decisions to be endorsed, thereby acknowledging the findings as an official interpretation of the Convention and the EU demonstrating its commitment to accepting the recommendations made and remedying any non-compliance, including through the subsequent interpretation of the new rules. Despite postponing the endorsement in the previous MOP, it is significant for the EU to politically demonstrate its commitment to be bound by the ACCC findings at the MOP and avoid setting a dangerous precedent, so far only established by Belarus in relation to ACCC findings against it on the harassment of environmental defenders.[228]

6.   Conclusion

This Article has shown that recent developments in access to justice in environmental matters offer a compelling perspective on the evolving nature of the autonomy of EU law. By examining the EU’s response to its obligations under the Aarhus Convention, it has highlighted the structural and normative tensions between maintaining the coherence and integrity of the EU’s legal order and ensuring compliance with international environmental standards. In doing so, the analysis has brought to light how the system of legal remedies in the EU, particularly the restrictive approach to standing before the CJEU and the complementary reliance on national courts, serves both as a reflection of and a mechanism for preserving EU autonomy. At the same time, the Article has underscored the critical role of NGOs in enforcing environmental law, and the extent to which their empowerment depends on meaningful access to justice at both EU and national levels.

Within this framework, the interplay between Article 263(4) TFEU and the Aarhus Regulation epitomises how the principle of autonomy operates in practice within the EU’s system of legal remedies. The Aarhus Regulation operates not as a freestanding remedy but as a legislative corrective to the structural limits of Article 263(4) TFEU. By maintaining a narrow interpretation of individual concern under the Plaumann standard, the CJEU has effectively excluded environmental NGOs from direct access to judicial review of EU acts. This gap in protection has driven successive amendments of the Aarhus Regulation, which the legislature has explicitly indicated as compensating for the limits inherent in Article 263(4). The interaction between the two mechanisms therefore illustrates a functional division of labour; Article 263(4) protects institutional autonomy and the coherence of the EU judicial system, while the internal review procedure seeks to give practical effect to the Union’s international obligations under the Aarhus Convention by ensuring that environmental challenges are not entirely foreclosed at EU level.

As identified at the outset of the Article, autonomy emerges not only as a doctrinal principle that is explicitly invoked in certain contexts. It also operates as a pervasive, though often implicit, thread, shaping the EU’s legal and institutional responses to its international obligations. The Article’s core contribution lies in illustrating that EU autonomy is not merely a defensive legal principle but a multidimensional construct that can facilitate or hinder the integration of international obligations. It argues that while autonomy enables the EU to mediate external influences through its own legal and institutional frameworks, this must not come at the expense of its credibility as an international actor upholding the rule of law. The challenge, therefore, is not to resist external legal obligations in the name of autonomy, but to recalibrate the balance between autonomy and compliance in a way that strengthens both the internal coherence and external legitimacy of the EU legal order, particularly in fields like environmental protection, where transnational cooperation and accountability are essential.

Furthermore, the Article demonstrates that the Aarhus Convention is not a narrow or technical treaty confined to environmental specialists. Instead, it directly engages questions that are central to EU external relations law: the scope of international obligations in a mixed agreement, the balance between Member State and EU competences, and the preservation of the CJEU’s authority in relation to international oversight mechanisms. In so doing, it reveals that debates about autonomy in the environmental field resonate far beyond it, touching on the EU’s constitutional self-understanding and its credibility as a global actor.

By analysing the EU’s responses to the ACCC findings, the Article shows how international compliance mechanisms can act as catalysts for internal legal reform. The successive amendments to the Aarhus Regulation and the introduction of a review mechanism for state aid decisions demonstrate how international pressure can penetrate the EU legal order despite the absence of traditional judicial enforcement. This is a distinctive feature of the Aarhus regime that enriches wider debates about the interaction between international and EU law.

The focus on access to justice highlights the close intersection of autonomy with fundamental rights and the rule of law. Autonomy here does not operate in an abstract or purely institutional sense; it conditions the availability of remedies for NGOs and citizens seeking to enforce environmental law. This perspective underscores the practical consequences of autonomy.

Finally, the Article contributes to broader debates about international accountability mechanisms. The ACCC’s role as a non-judicial body with significant interpretative authority over the Convention, and the EU’s sometimes resistant engagement with it, sheds light on how international oversight can shape EU law despite the Court of Justice’s traditional autonomy narrative. This aspect resonates with ongoing discussions about how the EU interacts with human rights bodies, investment tribunals, and other compliance mechanisms.

Ultimately, this Article shows that questions of access to justice in environmental law are, in fact, questions about the very identity of the EU legal order. By exposing the tensions between autonomy, international accountability, and fundamental rights, this field highlights not only the limits of the EU’s defensive stance but also the potential of autonomy to function as a constructive interface between internal coherence and external legitimacy. In this context, the direction that future case law may take will depend less on judicial creativity than on the broader equilibrium between institutional autonomy, international accountability, and fundamental rights. Whether the Court continues to privilege procedural coherence over expansive standing or instead gives fuller effect to Article 47 of the Charter as the constitutional foundation of effective judicial protection, the central question, therefore, is how the EU can preserve a system of remedies that maintains constitutional coherence while remaining credibly responsive to its international obligations. This balance, rather than any specific doctrinal reform, will determine the continuing legitimacy of the EU’s approach to access to justice in environmental matters.