How the digital infrastructure construction affects urban carbon emissions—A quasi-natural experiment from the “Broadband China” policy

The global emphasis on informatization and low-carbon development is growing. Using staggered Difference-In-Differences (DID) methodology, this research examines the impact of digital infrastructure development on urban carbon dioxide emissions and explores its underlying causal mechanisms. Drawing from a comprehensive 2009–2019 panel dataset of 240 Chinese cities, the study employs the “Broadband China” policy as a reliable proxy for digital infrastructure construction (DIC). The findings indicate that DIC effectively reduces urban carbon dioxide emissions, fostering sustainable low-carbon regional economic development. The results withstand robustness tests, revealing heterogeneous effects, with coastal cities and those with stronger environmental regulations experiencing more significant reductions. The study suggests that upgrading industrial structure and enhancing green innovation capacity are effective methods for DIC to mitigate urban carbon emissions. The paper concludes with policy recommendations, emphasizing leveraging policy dividends, addressing regional disparities, and adopting a multi-path development approach. Providing new insights and empirical data, this research contributes to understanding the relationship between DIC and urban carbon emissions, offering policy guidance for China's carbon reduction efforts and strategic objectives of carbon peaking and neutrality.