Congress sought to improve the nation's air quality beginning in the late 1960s with the passage of the Air Quality Act in 1967. following this first foray into regulation of air pollutants came the Clean Air Act of 1970 (CAA). The CAA was intended "to protect and enhance the quality of the Nation's air resources so as to promote the public health and welfare and the productive capacity of its population." The goal was to ensure that federal, state, and local governments took appropriate actions to prevent air pollution. Reduction of the emissions of certain pollutants was one of the major ways in which the problem of air pollution was to be remedied. To further this, the National Ambient Air Quality Standards (NAAQS) would be established to define the levels of allowable pollutants in the air to protect the public health and welfare of the nation. The 1970 Act also directed the creation of State Implementation Plans (SIPs) to enforce the standards. Furthermore, the Act created New Source Performance Standards (NSPS) which were developed to force the evolution of cleaner technologies and prevent significant deterioration of air quality. There were several major amendments of the CAA throughout the years and the EPA has worked to establish regulations that implement the framework of the Act.