Has the Sustainable Development Planning Policy Promoted the Green Transformation in China's Resource-based Cities

Scientific evaluation of the transformation effect of resource-based cities is an important way to measure the effect of the implementation of national transformation policies, and it is also an important issue in the study of China's urban transformation development under the "30-60 " goal of carbon peaking and carbon neutral. Based on the systematic understanding of the connotation of green transformation development in resource-based cities, this study constructed a framework for evaluating the green transformation performance (GTP) of resource-based cities in China, measured the GTP of 115 prefecture-level and above resource-based cities in China using the entropy weight-TOPSIS model, and further quantitatively assessed the policy effects of sus-tainable development planning (SDP) in China's resource-based cities from both the overall and local levels using synthetic control method. The results showed the following. (1) Time-series evolution characteristics analysis results showed that the average GTP allocation level of China's resource-based cities showed a steady upward trend in 2009 to 2018, from 0.4196 in 2009 to 0.4946 in 2018, an increase of 17.88%, and the growth rate showed a "W "-type fluctuating change characteristics. (2) Spatial differentiation characteristics analysis results showed that the average GTP allocation level of resource-based cities showed the heterogeneous characteristics of "east > middle > west ", "regenerative type > growth type > mature type > declining type ", and "ferrous metals > oil and gas > non-metals > forest industry > coal > non-ferrous metals ". (3) Overall policy effects analysis results showed that the implementation of the SDP policy had a weak positive promotion effect on the overall trans -formation and development of resource-based cities. The overall policy effect showed an "M "-type fluctuation trend, with a more obvious pushing effect at the early stage of policy implementation, and then showed a fluctuation and weakening trend. (4) Local policy effects analysis results showed that the implementation of the SDP policy had different impacts on the green transformation and development of different resource-based cities. This policy has positively promoted the GTP of mature cities (e.g., Panzhihua City) and declining cities (e.g., Jiaozuo City), while it has not significantly promoted the GTP of growth cities and regenerative cities. These findings can provide a reference for the optimization and improvement of sustainable development policies in resource-based cities in China.