The Impact of Digital Infrastructure on China's Green Total Factor Productivity: A Quasi-Natural Experiment Based on the “Broadband China” Pilot Policy

The digital economy has emerged as a crucial driving force for promoting China’s green transformation in the new development phase. The “Broadband China” initiative, a key policy aimed at fostering the digital economy, plays a significant role in enhancing green total factor productivity (GTFP). This paper, based on the "Broadband China" policy and panel data from 283 prefecture-level cities from 2009 to 2022, constructs a theoretical model and employs a multi-period difference-in-differences (DID) method to systematically analyze the impact of digital infrastructure development on urban green total factor productivity (GTFP) and its underlying mechanisms. The findings reveal that the “Broadband China” policy has significantly improved GTFP in pilot cities, with stronger effects observed in economically developed regions and large- to medium-sized cities. Mechanism analysis indicates that technological innovation, industrial structure optimization, and energy conservation and emission reduction are the main pathways through which digital infrastructure promotes the improvement of green total factor productivity (GTFP). The regional heterogeneity analysis reveals that policy effects are more significant in eastern regions and large or medium-sized cities, whereas the effects are relatively weaker in central and western regions and smaller cities. Robustness checks further validate the reliability of the research conclusions. Additionally, this study reveals the critical role of digital infrastructure development in enhancing green total factor productivity and promoting high-quality economic development from both theoretical and empirical perspectives. It provides valuable insights for optimizing digital infrastructure investment strategies and formulating regional development policies.