An ULEZ Ultra Low Emission Zone sign on the South Circular at Tulse Hill, on 21st July 2023, in London, England. Introduced by his Conservative predecessor Boris Johnson, London Mayor Sadiq Khan wants to expand the ULEZ area to a wider London to older vehicles such as polluting diesels and petrol cars, a controversial air quality policy to lower poisonous emissions that harms the health of 1 in 10 children. Drivers of non-exempt vehicles may enter the ULEZ after paying a £12.50 daily fee - or face a £160 penalty.