For each different type of tractor, the Directive lays down the maximum emission level on the basis of the engine power and provides for the gradual, phased reduction of emissions. On 31 December 2010, Stage III A ended, and on 1 January 2011 Stage III B began, which is to run until 31 December 2013.
La phase III A s'est achevée le 31 décembre 2010; la phase III B, commencée le 1 janvier 2011, s'achèvera le 31 décembre 2013.