Changes to Council Directive of 2 August 1972 on the approximation of the laws of the Member States relating to the measures to be taken against the emission of pollutants from diesel engines for use in vehicles (72/306/EEC)
EU Directive 1972/306
Made by Commission Directive 2005/21/EC of 7 March 2005 adapting to technical progress Council Directive 72/306/EEC on the approximation of the laws of the Member States relating to the measures to be taken against the emission of pollutants from diesel engines for use in vehicles
From legislation.gov.uk's record of changes, the official one: see it there.