California joined 13 other states and the District of Columbia in suing the Trump administration over what they say is a failure to enforce smog standards.
The suit announced Thursday says the U.S. Environmental Protection Agency has not designated any areas of the country as having unhealthy air, missing an October 1 deadline. Such designated areas must take steps to improve their air quality.
EPA spokeswoman Michele Huitric could not immediately comment on the suit filed Tuesday in federal court in San Francisco.
California Attorney General Xavier Becerra, who announced the lawsuit, says healthier air can save lives.
The suit also was filed by the attorneys general in Connecticut, Illinois, Iowa, Maine, Maryland, Massachusetts, New York, Oregon, Pennsylvania, Rhode Island, Vermont and Washington. Minnesota's Pollution Control Agency also joined the suit.