Case C-329/09 P: Judgment of the Court (Sixth Chamber) of 21 December 2011 — Iride SpA, formerly Azienda Mediterranea Gas e Acqua SpA v European Commission, A2A SpA, formerly ASM Brescia SpA (Appeal — State aid — Aid granted to public utilities — Tax exemptions — Decision declaring the aid scheme incompatible with the common market — Action for annulment — Admissibility — Standing — Legal interest)