Assessing the utility of low-emission pilot policies for facilitating pollution reduction and carbon mitigation: An empirical investigation using multi-temporal double difference analysis

Collaborative governance for pollution reduction and carbon mitigation can effectively resist the pressure brought about by ecological and environmental changes while reducing policy costs. To explore the "win-win" path of pollution reduction and carbon mitigation," based on panel data from 286 cities in China from 2000 to 2021, this study regards the low-carbon city pilot policy (LCCP) as a quasi-natural experiment and explores its impact on urban carbon emissions and pm2.5 concentration. Multiple testing methods, including multi-temporal double difference, spatial autocorrelation, local cold and hot spot analysis, kernel density analysis, standard deviation ellipse, spatial Durbin model, and PSM-DID, were used to verify the credibility and scientificity of the research results. The results showed that (1) LCCP had a direct effect on reducing pollution and carbon emissions, reducing co2 emissions by 3% and pm2.5 by 2.9%, with a synergistic effect of 20.2%; (2) the synergistic effect of LCCP on pollution and carbon reduction was indirectly achieved through green finance, green technological innovation, and green transportation, with impacts of 3.6%, 5.5%, and 2.4% in eastern, central, and non-resource based cities, respectively; and (3) the spillover effect coefficient of LCCP on carbon emission reduction in surrounding cities was -0.040 and that on pm2.5 concentration was -1.232, which are significant at the 10% and 1% levels, respectively.