Research On The Environmental Effect Of Regional Integration In Yangtze River Delta

The Yangtze River Delta region has the highest economic dynamism,the strongest innovation capacity and competitiveness,and it is also the most mature region of regional integration in China.With the development of the integration of Yangtze River Delta and the increase of cities integrated into the region,the requirements of the regional urban environment coordinated governance become higher.Especially in the context of the Yangtze River Delta integration as a national strategy,it is particularly important to pursue high-quality integrated development in an ecologically green manner.Firstly,this study analyses the current state of environmental pollution in 41 cities in the Yangtze River Delta region,and further constructs a comprehensive index of environmental pollution using the entropy method to provide a comprehensive analysis of the temporal trends and spatial variations of environmental pollution in the Yangtze River Delta region.Secondly,based on the panel data of 225 cities in China from 2003 to 2019,and using the quasi-natural experiment of the expansion of the Yangtze River Delta urban agglomeration in 2010 as the object of examination,this paper uses difference-in-difference method to evaluate the environment effects of regional integration.It further compares the environmental effects of the expansion policy on incumbent cities and new cities,and expands the analysis of the heterogeneity of the urban characteristics.Finally,the mediating model and the spatial econometric model were used to test the mechanisms by which regional integration in the Yangtze River Delta affects environmental pollution.The results showed that:(1)In terms of time trend,the environmental quality of the Yangtze River Delta has improved,but the improvement effect is not stable,in terms of spatial distribution,the space pattern of environmental pollution has changed from gathering to decentralized.(2)The regional integration of the Yangtze River Delta can effectively reduce the environmental pollution of the cities.After the parallel trend test and a series of stable tests,the conclusion is still effective.However,further analysis reveals that the enlargement of urban cluster has increased environmental pollution in the new cities while reducing environmental pollution in the original cities.(3)Heterogeneous analysis shows that the regional integration of the Yangtze River Delta has a better environmental governance effect in non-resource-based cities and high-level administrative cities large-scale cities.(4)The further mechanism analysis shows that the regional integration in the Yangtze River Delta can achieve regional pollution reduction through economies of scale,green technology innovation and industrial structure upgrading.And the regional integration has a significant spatial spillover effect on environmental pollution,the level of environmental pollution reduced in pilot areas while it increased in neighbor.Based on the above conclusions,the following policy suggestions are proposed:(1)Strengthen the systematic and overall view of environmental governance in urban agglomeration,and give a better play to the demonstration role of central cities.(2)Implement differentiated regional environmental governance measures in accordance with urban characteristics.(3)Give full play to the scale effects and technological overflow effects of the urban agglomeration,optimize the layout of the regional industrial structure,and realize the coordinated development of economy and environment.(4)Strengthen regional joint prevention and control,and comprehensively improve the effectiveness of regional environmental coordination governance.