Judgment of the Court (Grand Chamber) of 19 December 2019.#Deutsche Umwelthilfe eV v Freistaat Bayern.#Request for a preliminary ruling from the Bayerischer Verwaltungsgerichtshof.#Reference for a preliminary ruling — Environment — Article 6, the first paragraph of Article 47 and Article 52(1) of the Charter of Fundamental Rights of the European Union — Directive 2008/50/EC — Atmospheric pollution — Ambient air quality — Air quality plan — Limit values for nitrogen dioxide — Obligation to adopt appropriate measures to ensure that any exceedance period is very short — Obligation on the national courts to take any necessary measure — Refusal of a regional government to comply with an injunction — Coercive detention contemplated in respect of senior political representatives or senior officials of the region concerned — Effective judicial protection — Right to liberty of the person — Legal basis