London is experiencing record levels of air pollution this week, as a combination of Sahara desert dust mixed with industrial emissions from Europe has blanketed the city. The Guardian reports that the level of air pollution was ranked 9 out of 10 Thursday morning by the U.K.’s environmental officials, and that the cloud won't dissipate until at least Friday. South-east and eastern England, and Greater London are the areas most affected by pollution, although officials say it could move north to the east midlands.

The Houses of Parliament and the London Eye blanketed in smog.
AP / Lefteris Pitarakis

One in every eight deaths worldwide is linked to air pollution, according to a new report by the World Health Organization, and London is the latest major city to report severe problems from toxic pollution. Paris, another European capital blighted by thick smog, opened up public transportation for three days last month to ensure cars stayed off the road. And Beijing is experiencing something of a nuclear winter, after air pollution recently left the city without visibility for six days.

 A view of the Tower Bridge on the river Thames in
central London. AP / Lefteris Pitarakis

Authorities in Britain are warning people to avoid strenuous activity, especially those with heart and lung conditions. The BBC also reports that London Ambulance Service received a 14 percent increase in emergency calls related to breathing difficulties on Wednesday.

The pollution has even dented Prime Minister David Cameron’s daily routine. According to the BBC, Cameron said, "I didn't go for my morning run this morning, I chose to do some work instead, but you can feel it."