The coercive detention of persons for the purpose of enjoining them to adopt measures to improve ambient air quality can be ordered only if a national legal basis which is sufficiently accessible, precise and foreseeable in its application exists to that end and if the detention is proportionate.

Preliminary ruling referred by the Higher Administrative Court of Bavaria to the Court of Justice of the European Union (CJEU), to seek if the national courts have the faculty to impose coercive detentions to national authorities who refuse to comply with a judicial decision that compel them to run the obligations imposed by the European Union law.

In essence, the State of Bavaria, after the imposition of multiple coercive financial penalties, continued to refuse the adoption of measures imposed by the Directive 2008/50/CE, which oblige to respect the limit values of nitrogen dioxide emission in the cities. In this scenario, the non-governmental organization called “Deutsche Umwelthlife” promotes a new procedure requesting for a coercive detention that is foreseen in the german Code of Civil Procedure. In light of this, the national court refers a preliminary ruling with the aim of determining if the right of effective judicial protection (article 47 of the Charter of Fundamental Rights of the European Union) must be interpreted in the meaning that authorizes the national courts, or even, compels them to adopt such measure.

The decision of the CJEU is clear as it stablishes that, when competent authorities of a State member repeatedly refuse to accomplish with a judicial decision that obliges them to execute a clear, precise and unconditional obligation imposed by a Directive, the national courts have the competency to impose coercive detention as long as two requisites concur: that an statement of State law foresees it in a clear, accessible, precise and expected way and that the principle of proportion is respected.