Court of Justice 16 December 2010, C-165/09 to C-167/09 (Stichting Natuur en Milieu and Others v College van Gedeputeerde Staten van Groningen (C-165/09) and College van Gedeputeerde Staten van Zuid-Holland (C-166/09 and C-167/09).)

Opinion of the Advocate-General Opinion of the Advocate-General I – Introduction 1. As regards the protection of air quality, the European Union has set itself ambitious targets which leave Member States facing major challenges. That has already become apparent in cases on the quality of ambient air (2) and is confirmed in the present proceedings on national emission ceilings. 2.