Case C-120/19: Judgment of the Court (Third Chamber) of 20 May 2021 (request for a preliminary ruling from the Raad van State — Netherlands) — X v College van burgemeester en wethouders van de gemeente Purmerend (Reference for a preliminary ruling — Inland transport of dangerous goods — Directive 2008/68/EC — Article 5(1) — Concept of ‘construction requirement’ — Prohibition on laying down more stringent construction requirements — Authority of a Member State requiring a service station to be supplied with liquefied petroleum gas (LPG) only from road tankers fitted with a particular heat-resistant lining not provided for by the European Agreement concerning the International Carriage of Dangerous Goods by Road (ADR) — Unlawfulness — Decision legally unchallengeable by a category of persons — Strictly limited possibility of obtaining the annulment of such a decision where there is clear conflict with EU law — Principle of legal certainty — Principle of effectiveness)