From Pollution to Integration: How Environmental Quality Drives Urban–Rural Synergy in China

Urban–rural synergy (URS) is a key policy goal in China, yet environmental quality (EQ) is usually treated as an outcome rather than a driver of coordination. This study reverses that perspective. Using provincial panel data for 31 Chinese provinces from 2011 to 2023, we construct a multidimensional URS index and measure EQ with a composite air-pollution indicator. We estimate fixed-effects models, a spatial Durbin model, and threshold regressions with digital inclusive finance (DIF) as the threshold variable. Poorer EQ, measured by an inversely coded EQ proxy, is associated with lower overall URS. The pattern is strongest in the economic and demographic dimensions, while evidence for the social, spatial, and ecological dimensions is less consistent. Coastal–inland analysis shows that the positive role of environmental improvement is stronger in inland provinces. Spatial results indicate cross-provincial interdependence. Threshold analysis points to nonlinear heterogeneity across DIF regimes rather than a simple amplification effect. These findings link environmental governance more closely to balanced urban–rural development.