The Clean Air Act (CAA) is a comprehensive environmental law in the United States aimed at addressing air pollution and improving air quality. Enacted in 1963 and amended several times, its primary goal is to protect and enhance the nation's air resources. The law empowers the Environmental Protection Agency (EPA) to establish and enforce regulations for various pollutants, such as sulfur dioxide, nitrogen oxides, particulate matter, lead, and ozone. The CAA employs a combination of technology-based standards and ambient air quality standards to set limits on emissions from industrial sources, vehicles, and other contributors to air pollution. It has played a crucial role in reducing harmful pollutants, promoting public health, and safeguarding the environment. 

The CAA's regulatory framework includes provisions for state and local involvement, encouraging cooperation efforts to achieve and maintain air quality standards. It also addresses issues related to acid rain, ozone depletion, and hazardous air pollutants. The Act reflects the government's commitment to balancing economic development with environmental protection, aiming for sustainable progress in reducing air pollution and its associated health and environmental impacts.