How does a city’s digital economy development impact pollution emissions?

Introduction This study investigates the impact of urban digital economy development on pollution emissions across 285 Chinese cities from 2002-2022. Methods Utilising threshold regression, spatial autoregressive, and mediation models, we identify a nonlinear inverted U-shaped relationship where initial digital expansion initially elevates emissions before mature digital ecosystems drive reductions. Results Spatial heterogeneity reveals significant emission reductions in eastern/central regions versus limited effects in western/northeastern areas, while spatial spillover effects necessitate inter-regional policy coordination. Mediation analysis highlights green technology innovation and industrial upgrading as critical mitigating mechanisms. Discussion Findings advocate context-specific policies prioritising energy efficiency during digital emergence and advanced technology promotion in mature contexts, providing empirical groundwork for balancing digital economic benefits with environmental sustainability objectives.