Peer effects in urban pollution and carbon reduction: evidence from China

Cities are pivotal for pollution and carbon reduction (PCR) and clarifying peer effects among cities is essential for advancing interregional collaborative governance. This study, for the first time, cuts the perspective of peer effects to reveal the interactivity of urban PCR. We used data from 285 cities in China from 2015 to 2022 to explore the peer effects of urban PCR and their influence mechanisms. The findings indicate that urban PCR has positive and significant peer effects, which pass multiple robustness tests. Learning, promotion, and pressure mechanisms play key roles in shaping these effects. Cities can strengthen their peer effects through internal and external learning. Local officials in critical promotion periods exhibit heightened sensitivity to the effects, whereas excessive pursuit of the economy can weaken the effects. Moreover, cities with high environmental pressure and public concern are more attentive to their peers' PCR performances. Further analysis reveals that cities are more inclined to adopt avoidance convergence strategies than competitive convergence strategies, with peer effects peaking at distances of 100-200 km. This study offers new insights into inter-city environmental collaborative governance and provides particle reference for advancing regional PCR coordination mechanisms in China and other developing countries.