The Great Smog of London, or Great Smog in 1952, was a severe air pollution event that affected the capital of London in London in early December 1952. A period of cold weather, combined with anticyclone and non-windy conditions, collected air pollutants - most of which arose from the use of coal - to form a thick layer of smoke above the city. It lasted from Friday 5 December to Tuesday 9 December 1952, and spread quickly as the weather changed. This causes major disturbances by reducing visibility and even penetrating indoor areas, far more severe than previous smog events experienced in the past, called "pea-soupers". Government medical reports in the following weeks, however, estimate that until December 8, 4,000 people had died as a direct result of the smog and another 100,000 became ill by the effects of the smog on the human respiratory tract.] More recent studies have shown that the total number of deaths perhaps much larger, one paper th