Beginning of the Great Smog

Date: December 5, 1952 • Location: Bayswater, United Kingdom

The "Great Smog of London" (pictured) began and lasted for five days, causing 12,000 deaths and leading to the Clean Air Act 1956.

The Great Smog was a severe air pollution event that affected London, England, in December 1952. A period of unusually 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, then dispersed quickly when the weather changed.