The Impact and Mechanisms of the Sustainable Development Plan for Resource-Based Cities on Carbon Emission Efficiency

Using panel data from 282 prefecture-level and above cities in China, this study employs a difference-in-differences (DID) model to examine the impact of the National Sustainable Development Plan for Resource-Based Cities on carbon emission efficiency, as well as its underlying mechanisms and heterogeneous effects. The results indicate that the implementation of the Plan significantly improves carbon emission efficiency. This conclusion remains robust after a series of robustness tests, including the propensity score matching difference-in-differences (PSM-DID) approach. Mechanism analysis further reveals that technological innovation, industrial upgrading, and reductions in energy consumption constitute the primary channels through which the Plan enhances carbon emission efficiency. In addition, economic growth pressure and the degree of marketization exert negative and positive moderating effects, respectively, on the relationship between the Plan and carbon emission efficiency. Heterogeneity analysis shows that the positive effect of the Plan is significant only in resource-based cities located in eastern China, southern China, or southeast of the Hu Huanyong Line. In terms of city size, the positive effect is observed only in medium-sized cities and Type II large cities.