For decades, California has relied on the bureaucratic equivalent of a superpower: It has had special federal permission to make tougher air regulations than the U.S. government.
The origin of this dates back to the smog that began choking Los Angeles in the 1940s. After a scientist from the California Institute of Technology identified tailpipe emissions as a definite source of the eye-watering haze, California became the first state in the country to set limits for poisonous and smog-forming ingredients in vehicle exhaust.
California’s early lead on tackling air pollution set it apart. So when changes to the Clean Air Act decades ago stopped individual states from making their own tailpipe emissions rules, California got a pass. If California’s rules are just as tough, or tougher, than the federal ones, the EPA must grant it a waiver. There are only a few specific circumstances when the EPA can deny the waiver, including if it decides California is being “arbitrary and capricious,” or that California doesn’t actually need the waiver to address “compelling and extraordinary conditions.”