Add Yahoo as a preferred source to see more of our stories on Google. In 1952, London was blanketed under a dark cloud of human-made air pollution known as the Great Smog. The smog killed about 12,000 ...

London's poor air quality was an issue for centuries, but between Dec. 5 and 9, 1952, a perfect storm of weather patterns helped create a tragic event that killed thousands, later sparking the Clean ...