How Does the “Civilized City” Selection Affect Environmental Governance Performance? A Spatial DID Approach Based on Prefecture-Level Cities

Our study employs panel data from 272 Chinese prefecture-level cities (2003–2020), leveraging the “Civilized City” selection campaign as a quasi-natural experiment. Using a Spatial Durbin Difference-in-Differences model, we systematically analyze the policy’s impact on local environmental governance performance and its spatial spillover effects, with rigorous robustness checks. Results reveal a significant positive spatial correlation in China’s environmental governance performance, indicating interdependence among cities rather than isolated decision-making. The “Civilized City” initiative not only improves local environmental governance but also generates spillover benefits for neighboring regions, thereby enhancing coordinated regional sustainability. Finally, we propose policy recommendations grounded in empirical findings and China’s governance context.