California is leading a coalition of 22 Democratic states and the District of Columbia to defend in court the Environmental Protection Agency’s rule setting stringent greenhouse gas emissions standards for heavy-duty vehicles.

California Attorney General Rob Bonta, joined by Denver, Chicago, Los Angeles and New York, filed a motion last week to intervene in the U.S. Court of Appeals for the D.C. Circuit in defense of the EPA’s final greenhouse gas emission standards for heavy-duty vehicles, which is facing a legal challenge from Republican attorneys general.