Do Car Pollution Regulations Lead to Cleaner Air?

In his recent California speech on the environment, President Barack Obama said, “At the time when we passed the Clean Air Act, to try to get rid of some of this smog, some of the same doomsayers were saying, ‘New pollution standards will decimate the auto industry.’ Guess what? It didn’t happen. Our air got cleaner.” PoliticFact.com rates his claim.