A divided U.S. Supreme Court said Thursday that Republican states and industry groups are “likely to prevail” in their challenge to the U.S. Environmental Protection Agency’s Good Neighbor Plan to improve air quality and agreed to block the plan while litigation continues.

In a 5-4 decision written by Justice Neil Gorsuch, the court said the challengers were likely to succeed in their argument that the EPA’s rule announcing the air quality plan was not “reasonably explained.” The court therefore stayed enforcement of the plan while the parties continue to litigate the merits of the legal challenge in the lower courts.