The nonlinear effect of environmental regulations on urban green transformation in the Yellow River Basin

Chengzhen Song

In order to better achieve regional sustainable development, it is extremely important to explore the relationship between environmental regulation (ENR) and urban green transformation. Nonetheless, there is a dearth of research that examines the nonlinear relationship between the ENR and urban green transformation. Taking the Yellow River Basin (YERB) as a case study, this paper uses a panel Tobit model to investigate the nonlinear impact of the ENR on urban green transformation efficiency (UGTE) and examines the mediating role of industrial agglomeration (AGG) and technological innovation (TEI). The findings demonstrate an inverted U-shaped nonlinear influence of the ENR on UGTE in the YERB. There is significant heterogeneity in the influence of the ENR on UGTE in the YERB. The influence of ENR on the UGTE shows a negative effect in the upper reaches, but it is nonlinear in the middle and lower reaches. The influence of ENR on UGTE of non-resource-based cities is negative, while the influence on UGTE of resource-based cities is nonlinear. Furthermore, ENR can improve UGTE in the YRB through TEI, but there is a threshold effect in this process.