The exhaust emissions standards for new cars sold in the European Union are defined by legislation adopted by the EU.
The standards govern the limits on pollutants emitted in car exhaust gas (sulphur dioxide, nitrogen oxides, hydrocarbons, carbon monoxide, carbon dioxide and diesel exhaust particulates).
The more stringent Euro 4 limits became fully effective on January 1, 2007. Euro 5 and Euro 6 limits were introduced in June 2007. New model types may now be approved to the Euro 5 standard. This is compulsory for all new cars after January 2011.
A representative unit from each model type is tested, either by independent test organisations, or by the manufacturers or importers themselves at their own test facilities. The results have to be verified by the DfT.