Clean Air Zones
ULEZ, CAZ and congestion charges explained simply for UK drivers. The aim is quick clarity: will this journey cost you money today?
Quick answer
Clean Air Zone charges depend on the city, vehicle type and emissions standard. London uses its own ULEZ and Congestion Charge systems, while English Clean Air Zones use the GOV.UK checker. Always check your number plate before travelling.
ULEZ, CAZ and Congestion Charge are not the same thing
Many drivers mix them together, but they answer different questions.
Ultra Low Emission Zone. Mainly about vehicle emissions standards in London.
Emissions-basedCity clean air schemes outside London. Some classes affect cars; others mainly affect taxis, vans, buses and HGVs.
City-specificCentral London traffic charge. It is not an emissions charge, so cleaner vehicles may still need to pay.
Traffic-basedCurrent Clean Air Zones in England
Clean Air Zones are grouped into classes. Class D can include cars, while Classes B and C mainly affect larger or commercial vehicles depending on the local scheme.
Class C zone. Mainly affects higher-emission taxis, vans, minibuses, buses, coaches and HGVs.
Class D zone. Private cars may be charged if they do not meet required emissions standards.
Class C zone. Focuses mainly on taxis, vans, minibuses, buses, coaches and HGVs.
Class D zone. Private cars may be charged if non-compliant.
Class B zone. Private cars, motorcycles and vans are not charged under the Portsmouth CAZ.
Class C zone. Mainly affects taxis, vans, minibuses, buses, coaches and HGVs.
Newcastle and Gateshead Class C zone. Mainly affects commercial and larger vehicles.
London is different. Use TfL tools for ULEZ, LEZ and Congestion Charge instead of the GOV.UK CAZ checker.
Charges and exemptions can change. Treat this as a simple guide, then confirm your exact vehicle on the official checker before driving.
How to check before you drive
Check whether your journey enters a CAZ, ULEZ, LEZ or Congestion Charge area.
Use your vehicle registration number on the official checker for that city.
If a charge applies, pay through the official site. Avoid unofficial payment websites.
Common myths
Not always. EVs may avoid emissions charges, but congestion or tunnel charges can still apply.
No. Some zones focus on taxis, vans, buses, coaches and HGVs rather than private cars.
No. ULEZ is emissions-based; Congestion Charge is a central London traffic charge.
Not necessarily. MOT roadworthiness is different from emissions-zone compliance.
Quick answers
No. Birmingham and Bristol are the main English CAZ examples where private cars may be charged if non-compliant.
London ULEZ operates 24 hours a day, every day except Christmas Day.
Yes. You may need to pay Congestion Charge even if your vehicle meets ULEZ standards.
For many CAZ checks, petrol cars generally need Euro 4 and diesel cars generally need Euro 6, but always confirm officially.
Useful official links
Use these official services for final checks and payments.