By a 5-4 vote, the court's conservative majority ruled that the Environmental Protection Agency overstepped its authority under the Clean Water Act with water pollution permits that contain vague requirements for maintaining water quality. The decision is the latest in which conservative justices have reined in pollution control efforts.

The U.S. Supreme Court dealt a blow to the Environmental Protection Agency in a ruling on Tuesday involving a wastewater treatment facility owned by the city of San Francisco that could make it harder for regulators to police water pollution.

The 5-to-4 decision is the latest setback for the agency and could have sweeping implications for curtailing water pollution offshore.