When Congress passed the Clean Air Act in 1970, California was given a unique exemption due to its pre-existing standards. This waiver system recognized the state’s ongoing environmental leadership and its pressing need to combat pollution in densely populated urban centers.
Over the years, this authority allowed California to shape cleaner fuel blends, promote catalytic converters, and establish zero-emission vehicle programs. Other states, encouraged by California’s progress, began adopting similar measures under what’s known as Section 177 of the Clean Air Act.
