In December 1952 a temperature inversion trapped coal smoke and industrial pollution over London for several days, producing a smog so dense that transport halted and visibility fell to a few metres. Excess deaths in the following weeks were later estimated in the thousands, mainly from respiratory and cardiac causes. The disaster sharpened public concern over urban air quality. It led to the United Kingdom's Clean Air Act of 1956, which introduced smoke-control areas and restrictions on domestic and industrial emissions.
It established air pollution as a regulated urban hazard and prompted the smoke-control zoning and fuel restrictions that reshaped how cities manage their atmosphere.
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