How China's Zero-Waste City Pilot policy reduces urban carbon emissions: A Material-Energy-Economy perspective

Although the solid waste sector is one of the major sources of global greenhouse gas emissions, how solid waste governance reforms translate into city-level carbon mitigation remains unclear. Treating China's Zero-Waste City Pilot policy (ZWCP) as a quasi-natural experiment, this study uses panel data for 276 cities from 2010 to 2023 and applies a staggered Difference-in-Differences (DID) model to estimate its impact on total urban carbon emissions. It further explores potential transmission channels through a Material–Energy–Economy (MEE) framework. The results show that the ZWCP significantly reduces carbon emissions by approximately 4.6% (α₁= −0.047) on average, with the effect strengthening over time. Consistent with the MEE framework, the ZWCP is associated with increased municipal waste collection and waste-to-energy incineration capacity, reduced coal dependence and energy intensity, and improvements in industrial upgrading and green technological innovation. The mitigation effect is stronger in western, smaller, non-resource-based, and non-old-industrial-base cities, and is amplified by road infrastructure, green finance, and internet development. Overall, the ZWCP can effectively reduce urban carbon emissions when its implementation is tailored to local structural conditions and supported by complementary road, financial, and digital infrastructure.