How do you know that air quality improvements in inner and central London are a result of the ULEZ, rather than reduced traffic during the pandemic?

The pandemic had a significant but temporary impact on traffic, especially in central London. While this will have had an impact on air quality, the fact that vehicle compliance continues to grow within the existing ULEZ and pollution is not rising since traffic returned to pre-pandemic levels demonstrates the ongoing impact of the scheme.

Detailed analysis is set out in the Inner London ULEZ One Year Report.