London was hard hit in 1952, by what was termed as The Great Smog. It occurred for five days, from December 5 to December 9. The effect was death of more than 4000 people whereas about 100,000 people reported sick. This severe air-pollution event was result of a period of intensly cold weather, no wind conditions, and an anticyclone. As a result, airborne pollutants got trapped and couldn't rise above in the atmosphere. These pollutants were chiefly produced by the use of coal, both domestically and industrially.

The smog reduced the visibility severely and affected the people indoors also. The life of London came to a stand still. Even ambulances were not able to operate. Street lights were not able to penetrate the layer of smog. The government responded to this situation. Several acts were enacted and public awareness programmes were conducted.

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