Virginia and the Chesapeake Bay Foundation are suing the Trump administration over its rollback of fuel efficiency standards meant to limit tail-pipe pollution.

In separate lawsuits filed in federal court Wednesday, the Commonwealth and foundation joined dozens of other states, cities and organizations claiming the weakened emission guidelines violate federal environmental protections, including the Clean Air Act.

The previous emission standards, approved under President Barack Obama in 2012, required automakers’ fleets to average about 54 miles per gallon by 2025. Under the new rule, fleets need to average about 40 miles per gallon.

Carbon dioxide is one of the leading greenhouse gases that causes climate change. The organizations and states suing the administration say the rollback will lead to nearly a billion more metric tons of planet-warming carbon in the atmosphere.

“This replacement rule will not only make our air dirtier, putting the health of our children, seniors, and communities at risk, but it will also increase the climate change costs for individual states,” Virginia Attorney General Mark Herring said in a statement.

He noted that Hampton Roads is already experiencing effects from global warming, including sea level rise and worsening flooding. According to the Hampton Roads Planning Commission District, the region should prepare for at least 1.5 feet of higher water by 2050 and 3 feet by 2080.

The Chesapeake Bay Foundation added that the reduced standards threaten the restoration of the Chesapeake Bay and make it more vulnerable to climate change.

“Clean cars are essential to the Chesapeake Bay,” foundation attorney Ariel Solaski said. 

The foundation is co-plaintiffs with the Sierra Club, Union of Concerned Scientists and Center for Biological Diversity among other organizations. The 22 other states filing suit include Maryland, North Carolina, Rhode Island, Delaware, Massachusetts, New York and California.

President Donald Trump has said the new standards will make cars cheaper. It’s part of an overall effort by the administration to cut environmental regulations it deems burdensome, expensive and unnecessary.

Critics of the new fuel emission standards have pushed back, saying the policy will actually cost consumers more money by purchasing about 80 million gallons of additional gas.