Assessing the total factor performance of wastewater treatment in China: A city-level analysis

China is currently facing huge challenges in mitigating water shortages and protecting water bodies. The inferior wastewater treatment of the country has become the main barrier impeding regional water pollution control and sustainable economic development. Therefore, creating an overview of the current performance and weaknesses of city-level wastewater treatment is crucial and beneficial for exploring the driving factors for improvement. This study employed the slack-based measure and improved Luenberger productivity indicator decomposition method to investigate wastewater treatment performance in Chinese cities from static and dynamic perspectives. Results showed that pollutants were the main factors leading to wastewater treatment inefficiency. The total factor productivity of wastewater treatment (WTFP) of Chinese cities demonstrated an increasing trend from a temporal perspective and distinct spatial heterogeneity. An in-depth decomposition revealed that the most influential factor leading to WTFP growth was efficiency improvement rather than technical progress, pollutants discharge reduction rather than intensification of inputs. Given the varied types of cities, corresponding optimal and differentiated strategies, including source-oriented controls and end-of-pipe-led regulations, were provided to improve the overall performance of wastewater treatment. The findings of this study can help decision makers design specific policies for wastewater governance, which would be beneficial for achieving the green and high-quality development targets.