The smog is toxic (poisonous) fog. Long a classic example of the city over which he ruled was able, was considered to be London. Still not forgotten in England, the tragedy of December, 1952, when the smog has become a cause of premature death by about 4 thousand people suffering from cardiovascular diseases. It is a sad event made in 1956 to adopt the law on air protection, summoning him to build a large thermal stations giant chimney height up to 415 meters. This measure has helped to significantly reduce the concentration of harmful substances in the atmosphere. Although the total amount of pollution has decreased slightly over the London ceased to hang destructive smog.
The term "smog" was formed as a result of the addition of two English words: "smoke" (smoke) and "fog" (fog)denoting respectively the smoke and fog. In the city, where part of the guests fogs, industrial development has created this terrible monster - misty smoke. In windless days yellow poisonous cloud hung over the blocks. Sunlight contributed to chemical reactions between the particles of smoke, which was formed very harmful to people's health connection. They caused the cough, watery eyes, and even respiratory arrest. Mist, infused with coal dust and smoke hung over the city for weeks, and thousands of citizens were literally suffocating in it. Contributed to the formation of smog and thousands of pure London fireplaces, centuries Captiva heaven.
Currently, the number of fires is minimized. The remainder is often used smokeless coal.
After adoption of the law on protection of air within greater London's infamous London smog has become as rare as previously blue sky.