“…The SBM model improves the measurement accuracy of the ecological economic efficiency of decision-making units by constructing multiple input indicators and desired and undesired output indicators and directly adding slack variables to the objective function [28,30]. Thereafter, super-efficiency DEA models (the S-CCR model [24] S-SBM model [31]) for improving the accuracy and discrimination of ecological economic efficiency, cross-efficiency DEA models (the C-SBM model [32]), and network-efficiency DEA models that consider the input-output immediate process (the N-SBM model [25]) were constructed separately to measure ecological economic efficiency more objectively and comprehensively. Note: I indicates the discharge amount of industrial wastewater, the emission amount of industrial waste gas; II indicates the number of residents enjoying black water purification service, the amount of urban garbage collected by classification, the total power of photovoltaic power stations installed on the roofs of public buildings, the total amount of urban green space available to the public, the number of public transport passengers, and the number of vehicles classified as pollution-free; III indicates household water consumption, unclassified urban garbage collection, household natural gas consumption, household electricity consumption, days when the air quality threshold of particulate matter with less than or equal to 10 microns in diameter (PM 10 ) exceeds and the number of vehicles classified as polluted; IV indicates researchers in R & D, high technology export, electricity production from renewable sources, and the number of ISO 14001 certificates.…”