Case C-197/18: Judgment of the Court (First Chamber) of 3 October 2019 (request for a preliminary ruling from the Verwaltungsgericht Wien — Austria) — Proceedings brought by Wasserleitungsverband Nördliches Burgenland, Robert Prandl, Gemeinde Zillingdorf (Reference for a preliminary ruling — Environment — Directive 91/676/EEC — Protection of waters against pollution caused by nitrates from agricultural sources — Objective of reducing pollution — Waters affected by pollution — Maximum nitrate level of 50 mg/l — Action programmes adopted by the Member States — Rights of individuals to have such a programme amended — Locus standi before the national authorities and courts)