European emission standards define acceptable limits for exhaust emissions of new vehicles sold in EU member states. The emission standards defined in a series of European Union directives staging the progressive introduction of increasingly stringent standards. Currently, emissions of Nitrogen oxides (NOx), Total hydrocarbon (THC), Non-methane hydrocarbons (NMHC), Carbon monoxide (CO) and particulate matter (PM) are regulated for most vehicle types, including cars, lorries, tractors and similar machinery, barges, but excluding seagoing ships and aero planes. For each vehicle type, different standards apply. Compliance is determined by running the engine at a standardized test cycle. Non-compliant vehicles cannot be sold in the EU, but new standards do not apply to vehicles already on the roads. No use of specific technologies is mandated to meet the standards, though available technology considered when setting the standards. New models introduced must meet current or planned standards, but minor lifecycle model revisions may continue to offered with pre-compliant engines. In the early 2000s, Australia began harmonizing Australian Design Rule certification for new motor vehicle emissions with Euro categories. Euro III was introduced on 1 January 2006 and is progressively being introduced to align with European introduction dates.


see more in http://en.wikipediawiki/European_emission_standards
http://dieselnetstandards/eu/ld.php