Great Smog of London

The Great Smog of London was a severe air pollution episode in the first week of December 1952, when a cold, windless anticyclone trapped smoke from coal fires and industry over the city. A thick yellow-black fog covered London for about five days, reducing visibility to a few meters, halting road and rail traffic and forcing cinemas and theaters to close. About four thousand deaths were attributed to it at the time, and later studies suggested that the real toll was much higher, perhaps ten to twelve thousand, mainly from respiratory illness. The disaster led to the Clean Air Act of 1956, which created smokeless zones and encouraged a switch from coal to gas, electricity and cleaner fuels, and it is a landmark in the history of environmental policy.

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