The Supreme Court voted 5-4 to halt the Environmental Protection Agency’s (EPA) “Good Neighbor Rule,” which regulates interstate air pollution, in a ruling Thursday, the latest move by the conservative-dominated court against the environmental agency’s regulatory authority.

In the majority opinion, Justice Neil Gorsuch granted a request from Ohio, Indiana and West Virginia to temporarily block the rule while litigation against it proceeds through lower courts. Gorsuch, whose mother, Anne, was EPA administrator under President Reagan, wrote that “we see one reason for caution after another” in allowing the rule to proceed.