Study on the Synergistic Effect of Pollution Reduction and Carbon Emission Reduction in the Construction of “Zero-Waste Cities”

This study approaches the “Zero-Waste City (ZWC)” initiative as a quasi-natural experiment. Utilizing panel data from 273 prefecture-level cities in China from 2013 to 2023, it employs a multi-period difference-in-differences model to systematically assess the initiative’s synergistic impacts on pollution and carbon emission (CE) reductions. The findings indicate that the initiative has notably lowered both urban pollution and CEs. These results remain robust following a series of stability tests, which include dynamic effect analyses, placebo tests, and propensity score matching. Mechanism analysis suggests that the policy primarily achieves its pollution and carbon reduction goals through four pathways: green technological innovation, public participation and oversight, source control, and end-of-pipe treatment. Heterogeneity analysis further demonstrates that the policy’s effects are more pronounced in resource-based cities, regions with advanced digitalization, and areas with stringent environmental regulations. Additionally, “ZWC” initiatives notably enhance synergies between pollution reduction and carbon mitigation, especially in controlling pollutants closely associated with energy consumption, such as sulfur dioxide and particulate matter. This research provides empirical evidence and policy recommendations for promoting “ZWC” development and optimizing environmental governance systems. © 2025 by the authors.