An image of the Clean Air Zone symbol of a cloud in a circle
An illustration of lungs
An illustration of a car

A Clean Air Zone (CAZ) is a targeted measure taken to improve air quality resulting from pollution from vehicles

A CAZ aims to reduce Nitrogen Dioxide (NO2) emissions which are harmful to human health

A charging CAZ imposes a charge on non-compliant vehicles when entering a distinguished boundary, dependent on vehicle type. Non-compliance is determined by a vehicle’s Euro standard.

Types of Clean Air Zone

CAZs are categorised from Class A to D, with CAZ D being the strictest form

Each CAZ type imposes restrictions on specified vehicle types and fuel types

If vehicles are older than the specified minimum Euro Standard based on their fuel type, they will be charged for entering the CAZ boundary

The minimum requirement for cars, vans and taxis will be Euro VI Diesel (manufactured after September 2015) and/or Euro IV petrol (manufactured after January 2006).

The minimum requirement for HGV and Buses/Coaches will be Euro VI (manufactured after September 2015)

You can check your vehicle’s compliance here:



Diagram showing CAZ types

Liverpool Clean Air Zone Options

  • The four classes of CAZ are currently being assessed for Liverpool
  • Non-compliant vehicles will be charged unless exempt (exemptions to be confirmed)

  • Additional measures are also being examined to further improve air quality in Liverpool and to support non-compliant vehicle owner

Purpose of a Charging Clean Air Zone (CAZ)

A charging CAZ aims to achieve compliance with the defined air quality standards by:

1. Fewer Journeys


Fewer journeys through areas with poor air quality

2 Improve vehicle flow/movement

Improve vehicle movement through areas of poor air quality

3 Change of mode


Promoting travel on public transport, walking and cycling

4 Change where you are travelling to

Avoid travelling to/through areas of poor air quality

5 Change of route


Change route to avoid travelling through areas of poor air quality

6 Upgrading Vehicle


Cleaning up the emissions of essential trips through take up of cleaner vehicles