Smog episodes due to the combination of industrial pollutants and atmospheric
conditions in the Great Smog of London, lethal smog that covered the city of London
for five days, from December 5 to December 9, in 1952. It was caused by a combination of
industrial pollution and high-pressure weather conditions. The smoke and fog brought
London to a near standstill and resulted in thousands of deaths. Its consequences
prompted Parliament to pass the Clean Air Act four years later, which marked a turning
point in the history of environmentalism.
