U.S. law: 42 USC Sections 7401-7428 (1979) and resulting regulations in 40 CFR51, administered by USEPA. Its objective is to reduce atmospheric pollution to acceptable limits. Inter alia, it empowers local authorities to declare smoke control areas in which the emission of any smoke from chimneys will constitute an offense. The act became part of Great Britain's national legislation in July 1956, although its main provisions did not become effective until June 1, 1958.