But justices declined to block business group and red state suits against tougher curbs on mercury pollutants from coal-fired power plants and methane emissions from oil and natural gas facilities. 

All sides are waiting for a U.S. Supreme Court ruling by the end of June in a big Clean Water Act case.

Judge rejects industry groups' request for a nationwide injunction on the Waters of the US rule, which sets federal protections for certain water bodies and wetlands.