The case of San Francisco v. EPA. The case centers on the EPA's use of "generic prohibitions" in discharge permits, which San Francisco argues are vague and fail to provide adequate notice of discharge limitations. The dispute hinges on the interpretation of Section 301(b)(1)(C) of the Clean Water Act, focusing on whether it allows limitations beyond specific effluent restrictions. The EPA contends these prohibitions are necessary when sufficient information for more precise limitations is unavailable, while San Francisco maintains they violate the Act's requirement for clear discharge limitations. The justices explore various aspects of the Clean Water Act, the permit process, and the practical implications of different interpretations.