Digital policies and environmental regulations: does policy synergy achieve greater urban ecological resilience?

As cities face rising ecological risks and traditional environmental regulations are often constrained by information gaps and high enforcement costs, the rapid expansion of digital policies has made cross-sector policy synergy increasingly important for strengthening urban ecological resilience. However, the direct effects, underlying mechanisms, and spatial spillovers of the synergy between digital policies and environmental regulations on urban ecological resilience remain underexplored. Using panel data for 235 prefecture-level cities from 2010–2024 and a quasi-experiment based on National Comprehensive Big Data Pilot Zones, this study applies difference-in-differences and difference-in-difference-in-differences models to identify the effects of digital policies, environmental regulations, and their synergy on urban ecological resilience. The empirical findings indicate that policy synergy significantly increases urban ecological resilience by 0.6435, with ecological adaptability accounting for the largest improvement, whereas the effects on ecological resistance and recovery are relatively limited. This effect is mainly driven by the technology catch-up effect, energy decoupling, and the enhancement of environmental awareness. The synergistic effects are more pronounced in cities with lower economic development and weaker ecological foundations, contributing to a narrowing of regional disparities. Further analysis suggests that positive spatial spillovers to neighboring cities exceed local effects and attenuate with distance. These results offer guidance for easing urbanization pressures and supporting sustainable transitions.