Case C-128/17: Judgment of the Court (Sixth Chamber) of 13 March 2019 — Republic of Poland v European Parliament, Council of the European Union (Action for annulment — Directive (EU) 2016/2284 — Reduction of national emissions of certain atmospheric pollutants — Adoption of EU legal acts — Functioning of the legislative procedure — Article 4(3) TEU — Principle of cooperation in good faith — Actual exercise of the EU legislature’s powers of discretion — Impact assessment — Sufficient assessment of the effects of the contested act — Article 5(4) TEU — Principle of proportionality — Article 4(2) TEU — Equality of Member States before the Treaties — Article 191(2) TFEU — EU policy on the environment — Account taken of the diversity of the EU regions — Judicial review)