Municipal Ecological Efficiency Assessment and Correlation Factors Decomposition Based on an Improved Environmental Data Envelopment Analysis Model

Under the "China's new norm" of paying more attention to structural optimization, innovative promotion and sustainable development, this paper reports on construction of a non-radial regional potential output measurement model that contains the assumptions of variable returns to scale (VRS) and decision making unit (DMU) heterogeneity by directional distance function. Each city in a city cluster was viewed as a DMU to measure the ecological efficiency level of the city cluster. Further, the meta-frontier Malmquist-Luenberger (MML) index was employed to assess the dynamic changes of the ecological efficiency. On this basis, empirical studies were conducted in Chang-ZhuTan City Cluster and Wuhan City Circle of the national resource-saving and environment-friendly society (Two-Oriented society) comprehensive reform pilot area. It was found that the dynamic ecological efficiencies for the two city clusters were both improved as a whole. The potential ecological efficiency differences were mainly caused by technological differences, with the technology gap presenting an expanding trend. In view of the existing problems, some policy suggestions were proposed to improve the ecological efficiency situation of the two city clusters. The suggestions mainly include; building a unified market for technology transformation and trading within the city cluster, enhancing promotion of advanced technologies towards non-central cities, strengthening promotion and covering mechanism for reform achievements, accelerating elimination of outdated production capacity, and further improving of the technology threshold for industry admittance.