Air pollution in London passed levels in Beijing this week, figures have shown, with popular wood burning stoves blamed for exacerbating the problem.

On Monday London mayor Sadiq Khan issued the highest air pollution alert in London for the first time, and said on Tuesday that the capital’s ‘filthy air’ is now a ‘health crisis.’

Readings at 3pm on Monday showed that air at locations in the capital were worse than in notoriously smoggy Beijing, hitting a peak 197 micrograms per cubic metre for particulate matter on the Air Quality Index. Pollution in the Chinese city only reached 190, which is still deemed ‘unhealthy.’

Although nitrogen dioxide levels in London rose higher than China in 2014, it is believed to be the first time particulate readings have exceeded those in the far east.