This study investigates the impact of digital infrastructure construction (DIC) on carbon emissions (COE) using China's Broadband China Pilot (BBCP) policy as a quasi-natural experiment. Employing a Difference-in-Differences (DID) model with data from Chinese cities (2009-2019), the study finds that the BBCP policy significantly reduced COE. Robustness checks, including parallel trend tests, placebo tests, propensity score matching DID, and local projection DID, confirm this negative impact. Heterogeneity analysis reveals a stronger mitigation effect in non-resource-dependent cities, cities with higher green fund proportions, and those with lower fiscal expenditure. Mechanism analysis suggests that the policy's effect is mediated through industrial structure upgrading and green technological progress. The findings offer policy recommendations for developing countries aiming to achieve both digital transformation and low-COE development.

Zihao Lin