Sustainability Pathways and Policy Efficacy in a Rapidly Urbanizing Megacity

Shanghai's industrial dynamism and rapid urbanisation have put strain on numerous aquatic habitats, extending from the Huangpu and Suzhou Creek networks to the Yangtze River delta. The purpose of this study is to present both primary and secondary research on Shanghai's water-quality issues and assess the sustainability performance of major policies influencing the city's results: the Yangtze River Protection Law (2021–), the Sponge City Program (2014–), China's Water Pollution Prevention and Control Action Plan (the "Water Ten Plan," 2015), and national water reuse/resource recovery programs. We incorporate contemporary data on diffuse urban pollution, ecological consequences, and treatment/reuse trajectories using a sustainability perspective that includes pollutant reduction, climate resilience, equity, enforceability, and feasibility. The findings show that, in addition to legacy toxins, climate-exacerbated estuarine concerns, and persistent nonpoint pollution, basin-level improvements have occurred since 2015 due to the implemented policies, signaling progressive policy effectiveness and future resilience avenues ahead and beyond, with ongoing opportunities for adaptive management.