A Clean Air Zone (CAZ) is an area in the United Kingdom where targeted action is taken to improve air quality.

[citation needed] Whether a vehicle is charged when entering or moving through a CAZ depends on the type of vehicle and the Euro standard of the vehicle.

The amount charged is up to the local authority responsible for the CAZ.

Ultra-low-emission vehicles are not charged when entering or moving through a Clean Air Zone.

Greater London area 2021 and 2023)[e] area as the LEZ Operational 07:00 to 19:00 including Sundays cars in 2023)