Euro 6

European emission standards define the acceptable limits for exhaust emissions of new vehicles sold in EU and EEA member states. The emission standards are 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, trucks (lorries), locomotives, tractors and similar machinery, barges, but excluding seagoing ships and aeroplanes. For each vehicle type, different standards apply. Compliance is determined by running the engine at a standardised 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 is considered when setting the standards. New models introduced must meet current or planned standards, but minor lifecycle model revisions may continue to be offered with pre-compliant engines.

In the early 2000s, Australia began harmonising 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.

Also see the EU-mandated European on-board diagnostics.

Within the European Union, road transport is responsible for about 20% of all CO₂ emissions, with passenger cars and vans contributing about 15%.

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Wikipedia