To help improve air quality, TfL instigated an Ultra Low Emission Zone (ULEZ) on 8th April 2019. The ULEZ is active in the same area of central London as the Congestion Charge.
To find out where is affected you can use the interactive map on TfL’s ULEZ postcode search. They have also provided this downloadable PDF:
Vehicles affected include petrol cars and vans that do not meet Euro 4 standards (vehicles pre-2006) and diesel cars and vans that do not meet Euro 6 standards (vehicles pre-2015). Check your vehicle using TfL's online checker.
If vehicles don’t meet ULEZ emissions standards, their drivers must pay a daily charge to drive within the zone. The charge is £12.50 for cars, motorcycles and vans (up to and including 3.5 tonnes). It’s far higher for buses and lorries. The ULEZ charge is in addition to the Congestion Charge so be aware that you may have to pay both each day.
The ULEZ is to be expanded to cover all roads within the North and South Circular in 2021 in the hope that London's air will be within legal limits by 2025.
For more information on the charge and who is affected, please visit TfL’s ULEZ page.