The Great Smog of 1952 was a severe air pollution event that occurred in London from December 5 to December 9. A combination of cold weather, windless conditions, and heavy use of coal for heating led to a thick fog mixed with smoke and sulfur dioxide. This resulted in visibility dropping to just a few meters. The smog had serious health impacts, contributing to thousands of respiratory illnesses and an estimated 4,000 deaths. The event highlighted the dangers of air pollution, leading to increased public awareness and the eventual implementation of stricter air quality regulations in the United Kingdom.