<Tr> <Td_colspan="2"> 10,000 dead </Td> </Tr> <Tr> <Td_colspan="2"> 200,000 medical conditions </Td> </Tr> <P> 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 then dispersed quickly when the weather changed . </P> <P> It caused major disruption 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, 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 was considerably greater; about 6,000 more died in the following months as a result of the event . </P>

What factors led to the deadly smog in london in 1952