CLEAN AIR ACT

( in Britain ) any of a series of laws passed between 1956 and 1968 with the aim of making the air cleaner, especially by forbidding the burning of any fuel that produces smoke in certain areas. Before the first Clean Air Act of 1956, a mixture of smoke from coal fires and damp winter air produced the famous London smog (= smoke mixed with fog), which in some years caused the deaths of thousands of people.