Britain has three overlapping schemes with three sets of initials, which is why nobody can keep them straight. A Clean Air Zone (CAZ) is the English scheme, graded class A to D depending on which vehicles it charges. ULEZ is London’s, and it charges cars. LEZ is the Scottish scheme, and it does not charge at all — it fines.
If your car meets Euro 4 on petrol (roughly 2006 onwards) or Euro 6 on diesel (roughly September 2015 onwards), you pay nothing anywhere in the UK. Most cars on the road now clear it. The problem is concentrated in older diesels.
Which zones charge a private car
| City | Scheme | Daily charge for a non-compliant car | Standard to avoid it |
|---|---|---|---|
| London | ULEZ | £12.50 | Euro 4 petrol / Euro 6 diesel |
| Bristol | CAZ class D | £9 | Euro 4 petrol / Euro 6 diesel |
| Birmingham | CAZ class D | £8 | Euro 4 petrol / Euro 6 diesel |
| Oxford | Zero Emission Zone pilot | £2–£10 | Only electric and hydrogen are free |
| Bath, Bradford, Portsmouth, Sheffield, Newcastle, Tyneside | CAZ class B or C | No charge | Cars are outside the scheme |
| Glasgow, Edinburgh, Aberdeen, Dundee | LEZ (Scotland) | No charge — a penalty instead | Euro 4 petrol / Euro 6 diesel |
Charges and boundaries change; always confirm on the operating council’s own page and on gov.uk before travelling.
Scotland works differently, and it matters
English zones sell you a day. Scottish Low Emission Zones do not: there is no payment option. Drive a non-compliant vehicle into a Scottish LEZ and you receive a penalty charge notice, which doubles for each repeat offence within the same zone. There is no way to pay in advance and no way to make it legal for the day.
The practical consequence: in Birmingham an old diesel is an £8 nuisance. In Glasgow it is simply not allowed in.
How to check your own car in one minute
- Find your registration and the fuel type.
- Use the government’s vehicle checker for the zone you are travelling to — London has its own, the English CAZ cities share one on gov.uk.
- If it says compliant, nothing else is needed. There is no sticker, no registration, no permit.
Do not work it out from the registration year alone. Euro 6 diesels appeared before the standard became compulsory in September 2015, and some 2015 cars comply while others do not. The checker reads the actual type approval.
What it means when buying a car
- A pre-2015 diesel is the risk. It is the single largest group caught by every zone in the country, and it is the group whose used values have been most affected.
- Petrol from 2006 onwards is almost always fine — which is one reason a tidy older petrol hatchback has become a sensible city car again.
- Check before you buy, not after. If you live near a zone and commute through it, £12.50 a day is £3,000 a year — more than the car is likely to be worth.
- Zones are not the same as congestion charges. In central London you can owe both on the same day.
Clean air zones have nothing to do with vehicle tax, the MOT or your insurance. An old diesel can be perfectly legal, freshly tested, fully taxed — and still owe £12.50 every time it crosses the boundary. The two systems do not talk to each other.
Sources: zone list, charges and standards — Carwow UK low-emission zone guide; official checkers and rules — gov.uk clean air zones and TfL. Charges change — confirm before travelling. Last reviewed September 2026.