What requirement regarding motor vehicle emissions was established by the Clean Air Act of 1970?

The Clean Air Act of 1970 established a framework to control and reduce air pollution from various sources, with a significant focus on motor vehicle emissions. This legislation mandated the Environmental Protection Agency (EPA) to set and enforce National Ambient Air Quality Standards aimed at protecting public health and the environment. As part of this act, specific requirements were instituted to limit hazardous pollutants released from vehicles, necessitating emissions testing and the development of cleaner automotive technologies. This regulatory approach was crucial in addressing air quality issues related to the increasing number of vehicles on the road and their contribution to smog and other air pollution problems.

While the promotion of electric vehicle usage, development of alternative fuels, and incentives for public transport use are relevant to reducing emissions and improving air quality, they were not explicitly established as requirements by the Clean Air Act of 1970. The focus of the act at that time was primarily on controlling emissions from existing combustion engine vehicles.