thats not quite as it seems
the policies were also supported by the Conservative government:
(note this letter shared on social media is true, however the letter was in regard to extending the boundary to the extent of the South and North circular roads not greater London, so its true Sadiq Khan extended somewhat beyond the scope set by Conservatives
I would also point out that the measures Sadiq Khan put in place were also working towards the targets set by the Conservative govt in their Clean Air Strategy
This strategy sets out our plans for dealing with all sources of air pollution, making our air healthier to breathe, protecting nature and boosting the economy.
www.gov.uk