Effect and mechanism of digital infrastructure impacts the urban synergistic reduction of pollutant and carbon emissions.

The coordinated control of environmental pollutant and carbon emissions is a necessary condition for green growth. The digital economy has emerged as a major engine of sustainable and high-quality development. However, the effect of digital infrastructure (DI) on the synergistic reduction of pollutant and carbon emissions (SRPCE) is not clear. This study employes a two-way fixed effect model and Spatial Durbin Model to infer the impact of DI on SRPCE, and further propose the mechanisms behind these effects. The analyses were based on data from the 2011 to 2020 and 283 prefecture-level cities in China. Results show that: (1) DI has a significant promoting effect on SRPCE by 5.2%. (2) The potential channels of the effects were through improved energy efficiency, promoted industrial structure upgrading, and increased public environmental awareness. (3) There is a phenomenon of "spatial spillover effects", with DI significantly promoting SRPCE in adjacent areas (4) The heterogeneity analysis demonstrates that DI has its greatest positive effect on SRPCE in small and medium-sized cities, resource-based cities, and key environmental protection cities. These findings provide new insights for the government to urgently reinforce policy enforcement to reduce pollution and carbon emissions in the context of digital transformation.