Do regional integration policies matter? Evidence from a quasi-natural experiment on heterogeneous green innovation

In recent years, the governance crisis represented by air pollution, climate warming, and resource and environmental degradation has restricted the sustainable development of cities. Green innovation, characterized by low carbon intensity and efficiency, is an important way to solve the dilemma of resource constraints and ecosystem degradation. This paper constructs a quasi-natural experiment with China's regional integration policies as the shock, and studies the policy effects of heterogeneous green innovation from 2005 to 2019. The results show that: the impact of regional integration policies on total green innovation is dynamic and sustainable; regional integration policies can positively promote exploitative green innovation, but have no significant impact on exploratory green innovation; and the effects of regional integration policies on green innovation in cities of different sizes, locations, and pollution levels is heterogeneous. Future policy design should therefore pay more attention to the incentive effect of exploratory green innovation. •The ATEs and dynamic effect models of RIPs on HGI are constructed.•The positive effect of RIPs on green innovation is proven.•The green innovation of eastern megacities is restricted by RIPs.•Green innovation in polluted cities is more likely to be stimulated by policies.•The government should strengthen the incentive effect of exploratory green innovation.