Ecological regulation, leader localization, and synergistic governance of pollution reduction and carbon mitigation: Empirical evidence from China’s National Key Ecological Function Areas policy

Ecological regulation is a critical policy instrument for safeguarding ecological functions and improving environmental quality. This paper employs a difference-in-differences (DID) method and treats China’s National Key Ecological Function Areas (NKEFA) policy as a quasi-natural experiment. Drawing on panel data from 1847 counties spanning the period 2000–2020, it examines the impact of ecological regulation on the synergistic governance of pollution reduction and carbon mitigation (SGPC). The results reveal five key findings: (1) The implementation of the NKEFA policy significantly improves the level of SGPC, indicating a notable enhancement in local environmental quality. (2) The mechanism analysis indicates that the NKEFA policy primarily operates through three pathways: constraining urban expansion, reshaping industrial development, and incentivizing green technological innovation. (3) The moderation analysis shows that leader localization significantly strengthens the effectiveness of the NKEFA policy. (4) The temporal heterogeneity analysis indicates that the policy effect is stronger in the post-2015 period following the release of the “Overall Plan for the Reform of the Ecological Civilization System”, and the effect is more pronounced for the first batch of designated areas than for the second batch. (5) The spatial heterogeneity analysis reveals that policy effects vary substantially across different types of ecological function areas, while showing no discernible sensitivity to locational conditions or spillover effects from provincial capital cities. These findings offer theoretical support for the applicability of ecological regulation in developing countries and provide practical insights into the design of performance evaluation systems and incentive mechanisms in environmental governance.