All new vehicles sold in California must be certified under one of six emissions ratings by the California Air Resources Board (ARB). Emissions ratings indicate how much a new vehicle pollutes, and emissions are the result of the combined attributes of fuel type used, controls on the engine's operations and maintenance throughout the life of the vehicle.

DriveClean.ca.gov's Vehicle Search section features vehicles meeting the most stringent emissions ratings, as a guide for car buyers to identify vehicles polluting the least.

The ARB also provides a list of all California certified vehicles, which specifies the emissions rating for all vehicles sold in this state.