A study on synergistic development of urban digitalization and greening under the diffusion of low-carbon pilot policies

Low-carbon pilot policies, as comprehensive environmental strategies, provide a valuable perspective for examining the integrated development of urban digitalization and environmental sustainability. However, from the perspective of an integrated "pilot-diffusion" approach, the varying effects of pilot policies on the synergistic development of urban digitalization and greening, under different diffusion modes, are still not well clear. This study uses panel data from 278 Chinese cities between 2005 and 2022 and employs a double machine learning model to effectively control for high-dimensional confounders, reducing biases commonly associated with traditional methodologies. The results indicate that low-carbon city pilot policies effectively promote the synergistic development of urban digitalization and greening, with hierarchical diffusion demonstrating stronger policy effects compared to horizontal diffusion. Additionally, the upgrading of industrial structures and green technological innovation were found to regulate the effects of the policies, and the promotional effect of low-carbon pilot policies on the urban digitalization and greening development development of cities exhibits heterogeneity across different regions and city types. Through the analysis of policy diffusion patterns, this paper clarifies how different diffusion mechanisms influence policy outcomes, providing targeted policy recommendations and theoretical insights to support the coordinated progress of urban digitalization and greening. To enhance future low-carbon pilot policies, this paper emphasizes the need to adapt policy designs to specific diffusion modes and regional contexts, encouraging targeted and differentiated strategies to foster sustainable urban development.