SACRAMENTO, Calif. --- California and 15 other states sued the Bush administration Wednesday, Jan. 2, in hopes of overturning the Environmental Protection Agency's recent decision to block the states' efforts to establish their own emission standards for cars and trucks. The lawsuit was filed in the U.S. 9th Circuit Court of Appeals in San Francisco, the Los Angeles Times reported. Under the federal Clean Air Act, California can impose stricter air pollution laws than the federal government, as long as the state is issued a waiver from the EPA. In the past three decades, the agency has routinely granted such waivers. In turn, other states have had the option to adopt California's standards, rather than federal emission standards, if they are stricter. But in a letter to Gov. Arnold Schwarzenegger last month, EPA Administrator Stephen L. Johnson denied the state a waiver that would have given California authority to implement a 2002 state law seeking to cut greenhouse gas emissions from new vehicles by 30 percent over the next eight years. In the letter, Johnson wrote that the new federal fuel economy standards signed into law last month would lower greenhouse gases even more, making the California emissions law unnecessary. Further, the EPA has said that such standards need to be uniform for all 50 states --- a position echoed by representatives of the Alliance of Automobile Manufacturers. The Los Angeles Times reported that the outcome of the lawsuit may depend on whether California can demonstrate that its greenhouse gas law would effectively reduce emissions more than the new federal fuel economy standard. The new federal standard establishes a fleetwide average of 35 mpg for cars and light trucks by 2020. Johnson has stated that California's emission standards would translate into a 33.8 mpg fuel economy equivalent --- a figure strongly disputed by the California Air Resources Board technical staff. The 15 states joining California in the lawsuit are Massachusetts, Arizona, Connecticut, Delaware, Illinois, Maine, Maryland, New Jersey, New Mexico, New York, Oregon, Pennsylvania, Rhode Island, Vermont and Washington. In addition, five national environmental groups joined in the lawsuit.