The Trump administration signaled this week that it could end California’s long-standing authority to set its own limits on air pollution, largely over a disagreement regarding fuel efficiency standards. The administration faces an April 1 deadline to decide if more stringent fuel efficiency standards for cars and light trucks, established by the Obama administration, are attainable or need to be reworked. The federal government is seeking to leverage the waiver granted by Congress to California in 1970 that allows the state to set pollution standards that are more stringent than the federal Clean Air Act requires, using it as a wedge to convince California to agree to reductions in fuel efficiency standards. Automobile manufacturers are concerned that separate standards at the federal and California level – the state where more cars are sold than any other – would be overly burdensome.