Evaluating Pollution Reduction and Carbon Mitigation in China’s Zero-Waste Cities

Efficient waste management is instrumental in both reducing waste generation and mitigating CO2 emissions. The Zero-waste City Pilot (ZWCP) policy, a location-oriented waste governance initiative, aims to minimize waste production, enhance waste management efficiency, and improve resource utilization. Therefore, does the ZWCP policy achieve the dual environmental effect of pollution reduction and carbon mitigation? Based on panel data from 158 cities in China from 2011 to 2021, this paper employed a difference-in-differences (DID) model to empirically assess the impact of the ZWCP policy on solid waste and CO2 emissions. The results indicate that: (1) The ZWCP policy effectively reduced both solid waste and CO2 emissions, and the estimation results are robust as shown by robustness testing. (2) The policy achieved pollution reduction and carbon mitigation through two transmission mechanisms: stimulating green technological innovation and strengthening environmental regulation. (3) Heterogeneity analysis revealed that the policy’s effects on pollution reduction and carbon mitigation are more pronounced in central regions, non-resource-based cities, and large cities. (4) The ZWCP policy demonstrated no discernible enterprise exit effect, indicating its success in balancing environmental protection with economic growth, thereby providing a strong rationale for its extension to additional pilot regions. (5) The spatial spillover effect analysis revealed no significant spatial spillover of the ZWCP policy’s dual environmental effects. This may stem from the policy’s urban-centric implementation, uneven resource allocation and weak cross-regional collaboration mechanisms—factors that highlight the necessity for stronger cross-regional governance in waste management strategies. The study’s conclusions carry important policy implications for advancing China’s ecological civilization goals while provide valuable insights for other developing countries seeking to design effective zero-waste strategies.