Unravelling the nature of 'Do No Significant Harm': an emerging principle of EU environmental law or a transformative tool for the green economy?

This article critically examines the 'Do No Significant Harm' (DNSH) principle as introduced in the EU legal order with the European Green Deal and developed through EU secondary legislation. While the DNSH principle has become increasingly central in the EU's sustainable finance and is emerging as a condition for accessing EU funds, its legal nature and conceptual clarity remain ambiguous. To this end, this article aims to discuss whether the DNSH principle constitute a legal principle within EU environmental law and to explore its added value in promoting environmental sustainability in view of its emerging prominence as a horizontal tool and funding criterion. This article begins by tracing the development of the DNSH principle, from its origins in international law to its articulation in the European Green Deal and its incorporation into EU secondary legislation, particularly in the areas of sustainable finance (Taxonomy Regulation, Sustainable Finance Disclosure Regulation, Benchmarks Regulation) and the Recovery and Resilience Facility. The aim is to identify commonalities and divergences in how DNSH is implemented across these instruments, in order to assess its legal nature. Following this, the article evaluates the position of DNSH within the broader framework of EU environmental principles as set out in Articles 11 and 191 TFEU, aiming to further clarify its legal nature and function. Finally, it considers DNSH's contribution to internal coherence across environmental objectives, arguing that it adds concrete value by enhancing consistency and integration within EU environmental policy. The analysis ultimately suggests that, despite its legal codification and frequent reference as a 'principle', DNSH is better understood as a horizontal assessment tool, transformative in practice but conceptually distinct from the traditional principles of EU environmental law.