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CAZ, ULEZ and LEZ guide

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The UK has challenging legal obligations in relation to NO2 limits and is required to achieve compliance in the shortest possible time.

The government has identified a number of local authorities to develop local air quality plans to bring forward compliance dates within the shortest possible time. This can involve establishing charging clean air zones (CAZ). In some cases, HGVs classed as Euro V or below will incur a charge for entering a CAZ. The CAZ framework vehicle emissions standards are the same across CAZ, London ULEZ or LEZs in Scotland however which vehicles are in scope is at the discretion of the local authority.

Energy Saving Trust in partnership with Zemo runs the Clean Vehicle Retrofit Accreditation Scheme (CVRAS) which is a robust certification scheme for manufacturers to seek accreditation for any retrofit technologies that can bring a pre-Euro VI HDV up to Euro VI equivalent emission standards and provide lower-cost options for achieving clean air zone compliance. Further information is available here.

Only retrofit systems that are CVRAS approved will be recognised by local authorities implementing chargeable CAZs.