ULEZ
The Ultra Low Emission Zone is Transport for London’s clean-air charging area, covering all 32 London boroughs since August 2023. Petrol cars must meet Euro 4 (generally registered from 2006) and diesels Euro 6 (generally from September 2015) to enter free; anything else pays £12.50 a day. It operates 24 hours a day, every day except Christmas Day, and is enforced by number-plate cameras.
Example
A 2019 petrol hatchback is ULEZ compliant and pays nothing; a 2012 diesel SUV entering London pays £12.50 per day.