The emission reduction effect of industrial wastewater in the pilot city policy of water ecological civilization

As urbanization and industrialization accelerate, China's water resources are facing the double dilemma of inefficient utilization and serious pollution. This research employs the fixed effect difference-in-differences (DID) model to examine the impact of the country's industrial wastewater emission reduction policy in the pilot city for a water ecological civilization (PCWEC). The findings indicate after PCWEC implementation in 2013 that there was a notable decrease in the discharge of industrial wastewater in pilot cities compared to non-pilot cities, and that the policy's effectiveness exhibited a significant strengthening trend from 2014 to 2018. However, the interaction of total population, population density, fixed assets, regional GDP, total water resources, and proportion of the secondary industry in GDP has greatly weakened the policy's effect. Regional results show that compared to the east and central regions, the policy effect in the west region is more significant, whereby the gap between pilot cities and non-pilot cities in the east and central regions is narrowing. To expedite the construction of water ecological civilization in China, it is necessary to comprehensively strengthen the management of water conservation and formulate industrial structure policies according to local conditions.