Democratic attorneys general sued President Trump's Environmental Protection Agency on Wednesday, building on their crusade against the agency for not keeping smog-forming ozone out of their states.

Attorneys General Eric Schneiderman of New York and George Jepsen of Connecticut filed a lawsuit to force the EPA to stop ozone pollution that blows into New York and Connecticut from other states. The lawsuit was filed in the federal district court for southern New York.

The states' top lawyers described the suit as the latest action in a "multi-pronged initiative" led by Schneiderman to force the EPA to fulfill its obligations under the “Good Neighbor” clause of the federal Clean Air Act, requiring the agency to adopt plans to reduce interstate smog pollution when actions by upwind states are not sufficient.

“Millions of New Yorkers breathe unhealthy air due to smog pollution, much of which blows into New York from upwind states,” Schneiderman said. “Yet, the Trump EPA continues to ignore its responsibilities under the Clean Air Act to reduce interstate smog pollution. Since the Trump EPA refuses to follow the law, we’re suing to protect the health of New Yorkers.”

Wednesday's action follows another lawsuit against the EPA by Schneiderman and 14 other Northeast attorneys general for failing to meet a deadline for designating areas of the country affected by ground-level ozone pollution under a 2015 rule implemented by the previous administration.

In December, Schneiderman led a group of eight attorneys general in suing the EPA to meet the obligations of the Ozone Transport Region, which was created by Congress to address Northeast states' pervasive smog problems. The region includes Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, and the District of Columbia.

Schneiderman had asked the EPA to enforce the ozone regional obligations by submitting a petition to add nine states shown to be violating federal smog standards. Most of those states include coal states such as Ohio, West Virginia, Kentucky, and Illinois.

EPA Administrator Scott Pruitt formally rejected Schneiderman's petition in the fall.