1. By 30 September 2020, and every four years thereafter, the Commission, on the basis of information submitted by Member States in accordance with Article 18 and Article 21(2) and of information held in databases, as referred to in Article 21(3) and (4), and taking into account the implementation of Article 4, shall submit to the European Parliament and to the Council a report on the implementation and efficient functioning of this Directive, including information on major accidents that have occurred within the Union and their potential impact upon the implementation of this Directive. The Commission shall include in the first of those reports an assessment of the need to amend the scope of this Directive. Any report may, where appropriate, be accompanied by a legislative proposal.