Great Smog of London (1952)
Between December 5 and 9, 1952, London was choked by a deadly smog. Triggered by a temperature inversion that trapped coal smoke and industrial pollution at ground level, the “pea-souper” reduced visibility to near zero and paralyzed the city. Initially blamed for 4,000 deaths, later studies put the toll at 10,000–12,000, mostly from respiratory illness. The disaster spurred landmark reforms, leading to the Clean Air Act of 1956.
