# Dynamic Evaluation and Internal Driving Factors of Water Resources Green Efficiency in China
## 5 Conclusions and Recommendations  
### Conclusions  
This study utilized the HDDF-GML index model under from the perspective of mixed disposability to evaluate the dynamic changes of water resources green efficiency in China from 2000 to 2016. Furthermore, [PERSON]'s [46] decomposition method was used to study the inherent driving factors of water resources green efficiency. The main conclusions are as follows:  
Firstly, in terms of the time-varying characteristics of water resources green efficiency improvement, water resources green efficiency has improved overall (by 1.1%) between 2000 and 2016. The efficiency has improved the most in China's central region, with an increase of 1.4%, followed by that in the western region (1%), and the eastern region (0.9%). On a provincial level, the water resources green efficiency has improved in all provinces except Guangxi and Yunnan. In different time periods,  
Figure 11: Spatial differentiation characteristics of water resource green efficiency index: (**a**) Spatial differentiation of pure technology efficiency change (PEC), (**b**) Spatial differentiation of scale efficiency change (SEC), (**c**) Spatial differentiation of pure technology change (PTC) and (**d**) Spatial differentiation of scale technology change (STC).  
the number of provinces in which the water resources green efficiency has improved, deteriorated and unchanged has increased.  
Secondly, in terms of the spatial differentiation of water resources green efficiency improvement, the efficiencies in 14 provinces (Beijing, Shanxi, Inner Mongolia, Jilin, Heilongjiang, Jiangsu, Zhejiang, Anhui, Hubei, Chongqing, Sichuan, Guizhou, Gansu and Ningxia) are higher than the national level. In contrast, the rate of water resources green efficiency improvement in Tianjin, Hebei, Liaoning, Shanghai, Fujian, Jiangxi, Shandong, Henan, Hunan, Guangdong, Guangxi, Hainan, Yunnan, Shaanxi, Qinghai and Xinjiang is lower than the national level. The top ten provinces for improvement are Shanxi, Beijing, Inner Mongolia, Jiangsu, Ningxia, Anhui, Heilongjiang, Gansu, Chongqing and Zhejiang. From spatio-temporal analysis of green efficiency of water resources, it can be found that water resources green efficiency is significantly affected by national policies, but there may not be a significant positive correlation with economic development. At present, the water resources green efficiency in most provinces still needs to be improved.  
Thirdly, in terms of time-varying characteristics of water resources green efficiency decomposition, SEC has declined during 2000-2016 but the other three indices have increased. PTC is increasing faster than PEC and STC. Provinces in the eastern, central and western regions, as well as China nationally, should pay more attention to improving resource utilization under existing technical conditions in the process of increasing R & D investment.  
Finally, in terms of spatial differentiation characteristics of water resources green efficiency decomposition, the absolute and relative differences in water resources green efficiency among provinces since 2000 have been the same or similar. The inter-provincial differences of PEC are variable, and have decreased before increasing and then decreasing again. In contrast, the differences of SEC and STC have shown overall upward trends, and the difference of the PTC have decreased steadily after an initial increase. Except for Tianjin City and Qinghai, Gansu and Guizhou provinces, where the PTC is unchanged or decreasing, all other provinces are in a state of improvement. The proportions of provinces that exhibit improved PEC, SEC, and STC are 40%, 46.67%, and 60%, respectively.