The Great Smog of London, or Great Smog of 1952, was a severe air-pollution event that affected the British capital of London in early December 1952. A period of cold weather, combined with an anticyclone and windless conditions, collected airborne pollutants—mostly arising from the use of coal—to form a thick layer of smog over the city.
It lasted from Friday 5 December to Tuesday 9 December 1952, and dispersed quickly when the weather changed. It caused major disruption by reducing visibility and even penetrating indoor areas, far more severely than previous smog events experienced in the past, called "pea-soupers". Government medical reports in the following weeks, however, estimated that up until 8 December, 4,000 people had died as a direct result of the smog and 100,000 more were made ill by the smog's effects on the human respiratory tract.] More recent research suggests that the total number of fatalities may have been considerably greater, one paper suggesting about 6,000 more died in the following months as a result of the event
London had suffered since the 13th century from poor air quality, which worsened in the 1600s but the Great Smog is known to be the worst air-pollution event in the history of the United Kingdom and the most significant in terms of its effect on environmental research, government regulation, and public awareness of the relationship between air quality and health. It led to several changes in practices and regulations, including the Clean Air Act 1956.
