A right to clean air in EU law? Using litigation to progress from procedural to substantive environmental rights

European environmental NGOs increasingly resort to litigation as a tool to protect the environment. However, courts in the European Union often provide ‘a wide entrance, to a very small room’: the generous standing requirements available to the public under the Aarhus Convention clash with the narrow grounds for judicial review, which are limited to procedural issues. The recent history of clean air cases shows that litigation can push courts to review the substance of administrative decisions, overturning national legal traditions and, ultimately, leading to the development of a substantive right to a safe and healthy environment.