Why Do California DMV Require a Smog Check?

California's geography and climate can sometimes trap pollutants and result in smog, hence the state has some of the toughest air quality regulations in the nation. The Smog Check Program helps the state achieve national air quality standards by reducing passenger vehicle and light-duty truck emissions. In accordance with the California Air Resources Board (CARB), the smog check program eliminates approximately 400 tons of smog-causing pollutants from California's air daily.