In December 1970 Congress passed the Clean Air Act of 1970. It established a comprehensive air pollution control program. The act provided more than $1 billion for a three-year program, which set air-quality standards and tough emission guidelines for automakers. The act required model year 1975 cars to emit 90 percent less carbon monoxide and hydrocarbons than 1970 cars emitted. The act also specified that 1976 cars emit 90 percent less nitrogen oxides than 1971 cars. The head of the Environmental Protection Agency had to grant automakers an extension to meet the 1975 emission standards.
