Does financial agglomeration promote the green efficiency of water resources in China?

Whether financial agglomeration is conducive to improving the green efficiency of water resources is of great significance for China to realize water saving and consumption reduction, and green sustainable development. Based on the panel data of 30 provinces in China from 2006 to 2017, this paper uses the SBM model with undesirable output to measure the green efficiency of water resources in China and empirically examines the impact of financial agglomeration on the green efficiency of water resources. The results show that the green efficiency of water resources in China presents the "N" type fluctuation characteristic, and the overall trend is increasing. The mean value of green efficiency of water resources in China fluctuates around 0.6, which is at a medium level, and there is still a large room for improvement. Secondly, there are obvious spatial differences in China's green efficiency of water resources, showing a gradient of "Eastern>Central>Western." Thirdly, at the national level, financial agglomeration has a significant positive impact on the green efficiency of water resources, and there is an inverted "U"-shaped relationship between financial agglomeration and green efficiency of water resources. Fourthly, at the regional level, the impact of financial agglomeration on green efficiency of water resources has significant regional differences. Finally, based on the above conclusions, specific proposals for financial agglomeration to improve the green efficiency of water resources are put forward.