California is our nation’s environmental umbrella. Although the EPA generally has complete authority to set pollution standards for cars, Section 209 of the Clean Air Act grants CA the power to set its own emissions standards for new motor vehicles through the use of waivers, i.e. – CA has the ability to set a higher standard than the federal government. In addition, other states can opt into CA’s higher standards over the federal ones. 14 states, totaling 40% of the US’s population (states in green) have adopted CA’s standards. With such a large proportion of the nation’s autos covered by the higher standards, automakers are forced to abide by the higher standards or lose money making vehicles that meet two different regulations.
For forty years the EPA has granted all but one of the more than 100 waivers sought by CA and the single denial was later overturned.