<P> The Clean Air Act (42 U.S.C. § 7401) is a United States federal law designed to control air pollution on a national level . It is one of the United States' first and most influential modern environmental laws, and one of the most comprehensive air quality laws in the world . As with many other major U.S. federal environmental statutes, it is administered by the U.S. Environmental Protection Agency (EPA), in coordination with state, local, and tribal governments . Its implementing regulations are codified at 40 C.F.R. Subchapter C, Parts 50 - 97 . </P> <P> The 1955 Air Pollution Control Act was the first U.S. federal legislation that pertained to air pollution; it also provided funds for federal government research of air pollution . The first federal legislation to actually pertain to "controlling" air pollution was the Clean Air Act of 1963 . The 1963 act accomplished this by establishing a federal program within the U.S. Public Health Service and authorizing research into techniques for monitoring and controlling air pollution . </P> <P> It was first amended in 1965, by the Motor Vehicle Air Pollution Control Act, which authorized the federal government to set required standards for controlling the emission of pollutants from certain automobiles, beginning with the 1968 models . A second amendment, the Air Quality Act of 1967, enabled the federal government to increase its activities to investigate enforcing interstate air pollution transport, and, for the first time, to perform far - reaching ambient monitoring studies and stationary source inspections . The 1967 act also authorized expanded studies of air pollutant emission inventories, ambient monitoring techniques, and control techniques . Amendments approved in 1970 greatly expanded the federal mandate, requiring comprehensive federal and state regulations for both stationary (industrial) pollution sources and mobile sources . It also significantly expanded federal enforcement . Also, EPA was established on December 2, 1970 for the purpose of consolidating pertinent federal research, monitoring, standard - setting and enforcement activities into one agency that ensures environmental protection . </P> <P> Further amendments were made in 1990 to address the problems of acid rain, ozone depletion, and toxic air pollution, and to establish a national permit program for stationary sources, and increased enforcement authority . The amendments also established new auto gasoline reformulation requirements, set Reid vapor pressure (RVP) standards to control evaporative emissions from gasoline, and mandated new gasoline formulations sold from May to September in many states . Reviewing his tenure as EPA Administrator under President George H.W. Bush, William K. Reilly characterized passage of the 1990 amendments to the Clean Air Act as his most notable accomplishment . </P>

When was the clean water and air act originally enacted