What are Euro 6 emission standards?

Euro 6 emissions standards were introduced in 2015 to reduce harmful exhaust emissions from petrol and diesel cars and vans. 

Governments and car manufacturers have been working to lower emissions for years, with European emission standards playing a crucial role. These standards were first introduced in 1992 with Euro 1 and have become progressively stricter, leading up to Euro 6 in 2015.

Euro 6 not only measures how clean your car is but also determines whether you’ll be subject to charges, such as in London's Ultra Low Emissions Zone (ULEZ) and other Clean Air Zones (CAZ) across the UK. Read on to find out if your vehicle meets Euro 6 standards.

What does Euro 6 mean?

Euro 6 standards, introduced in September 2015, are the sixth generation of emissions regulations, following Euro 1 through 5. They aim to reduce pollutants such as nitrogen oxides (NOₓ), carbon monoxide (CO), hydrocarbons (HC), and particulate matter (PM) from vehicle exhausts.

These pollutants harm both the environment and human health. Looking ahead to 2026, Euro 7 standards are set to replace Euro 6, bringing even stricter emissions limits as well as regulating non-exhaust emissions, including pollutants from vehicle brakes and tyres.

Euro 6 and diesel cars

Euro 6 had a significant impact on diesel cars due to their higher NOx emissions. So, while diesels could produce 0.18g/km of NOx gases under Euro 5a emissions standards, this was reduced to 0.08g/km when Euro 6 came in. To meet these stricter limits, most modern diesel cars are fitted with Selective Catalytic Reduction (SCR) systems, which use AdBlue to neutralise NOx gases from exhaust emissions.

Euro 6 and petrol cars

Petrol cars were less affected by Euro 6 regulations because they already produced lower levels of NOx. For example, Euro 6 standards mean petrol cars can produce 0.06g/km of NOx gases and 0.005g/km of particulate matter  – exactly the same as Euro 5 emissions. However, Euro 6 introduced a PM limit of 0.005g/km for petrol vehicles, which particularly affected direct injection engines.

Euro 6 emissions standards and the London ULEZ

Euro 6 really matters to you if you're a diesel car owner living in London or other cities with a Clean Air Zone.

The Ultra Low Emissions Zone (ULEZ), which initially covered central London, expanded in 2023 to include all London boroughs. Several other UK cities, including Birmingham, Bristol, Bath, and Manchester, have introduced or are planning Clean Air Zones with varying restrictions.

Diesel cars that meet Euro 6 standards are exempt from paying the charge, but older diesel – typically sold before September 2015 – are charged £12.50 per day to enter the zone. For petrol cars, Euro 4 compliance is required to avoid charges. 

Euro 6 checker: how to see if your car is compliant?

The easiest way to check if you car is Euro 6 compliant is to enter your car's registration onto TFL's online tool or similar tools provided bvy local authorities running Clean Air Zones. These will tell you if your car meets Euro 6 standards and if you'll have to pay any extra fees should you drive into Low Emission Zones.