Signage on roads in and around the zone, showing a white cloud symbol within a green circle, will indicate that a Clean Air Zone scheme is in operation. A letter A–D will also be included on the symbol (see images below), denoting the class of zone that applies.

4 icons showing the white cloud in the green circle of a Clean Air Zone with each lettered A to D denoting the type of vehicles that are charged in the zone

The 4 x ascending lettered classes relate to the different groups of vehicle that are charged, as follows:

• Class A: Buses, coaches, taxis, private hire vehicles
• Class B: Buses, coaches, taxis, private hire vehicles, heavy goods vehicles
• Class C: Buses, coaches, taxis, private hire vehicles, heavy goods vehicles, vans, minibuses
• Class D: Buses, coaches, taxis, private hire vehicles, heavy goods vehicles, vans, minibuses, cars (the local authority also has the option to include motorcycles)

Please note that a number of Clean Air Zone exemptions and discounts apply to different zones.