Cycling in London is already a challenging, and even dangerous, proposition. Take the recent dooring of a cyclist by the British transport secretary, an incident which a prominent columnist in the Sunday Times called a “beautifully timed manoeuvre.” Beyond the dangers that can be seen come the invisible, namely the increase in air pollution.

The air in London is choked with pollution. What is this, the 19th century? https://t.co/eUpjS36y32 via @BV pic.twitter.com/NRASU9StMd

— Bloomberg (@business) January 23, 2017

Pollution levels in the capital have reached the highest levels ever of the past six years, with ‘black’ or ‘very high’ warnings issued. Mayor Sadiq Khan has told residents to act to protect their health from the “shameful state of London’s air.”

“With all the pollution warnings it is better safe than sorry, you can feel that the air is not healthy, it is definitely bad,” Dariuz Kabulski, 25, told the Evening Standard.

“It is not like you are suffocating but it is not pleasant. It is getting worse during the winter period. I would recommend using a mask, it’s not that comfortable but it’s definitely better than the results of breathing the air.”

“Air pollution continues to have a significant impact on people’s health in London but the Mayor and boroughs are working to address it,” the Mayor’s advisor on toxic air from Public Health England, Dr Yvonne Doyle, said.

Click through to read more at the Evening Standard.