What is the most important law passed to deal with air pollution?

The most important law passed to deal with air pollution is the Clean Air Act. The Clean Air Act was first passed in 1963 and has been amended several times since then. The act sets national air quality standards for pollutants such as ozone, particulate matter, sulfur dioxide, and nitrogen dioxide. The act also regulates emissions from sources such as power plants, factories, and motor vehicles. The Clean Air Act has been credited with helping to reduce air pollution in the United States by over 70% since 1970.