Ecological efficiency and its determining factors in an urban agglomeration in China: The Chengdu-Chongqing urban agglomeration

Urban agglomerations are the main driver of economic growth in China. The green development of less developed urban agglomerations, which have greatest potential for future economic growth, is of great importance. Otherwise, the old development path will lead to more energy and environmental issues. Therefore, assessing its level of sustainable development and understanding the determining factors of ecological efficiency is conducive to fulfilling green development goals. Based on the data pertaining to a typical less developed urban agglomeration (Chengdu-Chongqing) from 2003 to 2018, a super slack-based measure model with undesirable outputs is used to measure the ecological efficiency. The results show that the ecological efficiency of the Chengdu-Chongqing urban agglomeration is deteriorating over time. The ecological efficiency of big cities is lower due to the extensive development, and on contrary, the ecological efficiency of nearby small cities is high. The determining factors of the ecological efficiency are also investigated by the spatial panel model. Gross domestic product, social retail consumption, and population size are found to exert a positive influence. A 1% increase in these variables increases the ecological efficiency by 0.008, 0.011, and 0.015, respectively. Discussions are made according to the results and policy implications are proposed pursuant thereto.