ULEZ has not improved air quality in London as much as Sadiq Khan has claimed, according to data from local councils.

Last year, the Mayor of London credited the £12.50-per-day ultra low emission zone with bringing levels of nitrogen dioxide (NO2) across the capital to within legal limits for the first time.

But analysis of official air quality figures from local authorities suggests more than half of all boroughs are still recording illegal levels of the toxic gas, which is largely emitted from diesel vehicles.

Read more: Sadiq Khan’s £12.50-a-day ULEZ tax on drivers has not improved London air quality as much as mayor claims (but DOES rake in more than £200m a year…), new figures show