Attorney General Letitia James’s office Thursday filed a lawsuit challenging the U.S. Environmental Protection Agency’s smog regulations.

The concern is ground-level ozone pollution that enters New York from other states and the EPA’s 2018 “close-out” rule for controlling the smog from states upwind of New York.

The suit is among the first major legal challenges to the Trump administration James has filed since she became attorney general earlier this month.

“Over two-thirds of New Yorkers regularly breathe unhealthy air due to smog pollution,” James said in a statement. “Yet, Trump’s EPA is ignoring the Clean Air Act and refuses to require reductions in the pollution largely responsible for this serious public health risk. My office will stand firm for the quality of air in our state by forcing Trump’s EPA to follow the law and to ensure New Yorkers’ legal right to clean air.”

The suit was filed along with attorneys general in Connecticut, Delaware, Maryland, Massachusetts, and New Jersey as well as the city of New York.