Which case study illustrates successful pollution reduction and what strategies were involved?

• A. Clean Air Act
• B. Kyoto Protocol
• C. Great Lakes Water Quality Agreement
• D. Montreal Protocol

Answer: (C)

This item tests how a real-world pollution-reduction effort succeeds through targeted, collaborative actions within a shared environment. The Great Lakes Water Quality Agreement is a binational pact between the United States and Canada aimed at restoring the chemical, physical, and biological integrity of the Great Lakes basin. It shows how concrete strategies can work together to reduce pollution: cutting phosphorus loads to combat eutrophication, eliminating persistent toxic substances, upgrading wastewater treatment and controlling industrial discharges, and remediating contaminated sediments. The agreement is built on joint targets, regular data sharing, adaptive management, and ongoing monitoring to track progress and adjust actions as needed. In this way, it serves as a clear case study of how coordinated policy, practical source-control measures, and continuous evaluation lead to measurable improvements in water quality. The other options represent broader frameworks (air-focused legislation or international treaties on climate or ozone depletion) rather than a watershed-specific pollution-reduction effort with tangible strategies and outcomes.