Multi-Scale Spatial Assessment of Green Development and Environmental Quality in a Cross-Provincial Demonstration Zone Within the Yangtze River Delta Urban Agglomeration Using a Dual-Index Approach

Approaches for assessing the environmental outcomes of green development using quantitative indicators remain limited. This study integrates socioeconomic indicators with geospatial environmental information to assess green development level (GDL) and eco-environmental quality (EEQ) in a cross-provincial demonstration zone within China’s Yangtze River Delta (YRD) urban agglomeration covering three administrative districts and 28 townships from 2000 to 2020. GDL index was established using 38 indicators aligned with 13 Sustainable Development Goals (SDGs) across five sub-dimensions, while EEQ was measured using the Comprehensive Evaluation Index (CEI), a remotely sensed environmental index integrating PM2.5, land surface temperature, and vegetation coverage. The CEI represents environmental change relative to the year 2000 baseline rather than absolute environmental quality. Spatial and temporal analyses were conducted at the administrative district and township scales to examine the relationship between green development and environmental quality. The results showed that GDL increased consistently in all three districts from 2000 to 2020 in the study area, while EEQ followed a non-monotonic three-stage pattern, indicating a temporal mismatch between green development and environmental improvement. Moreover, this dual-index approach allows policymakers to distinguish regional development and environmental status within the administrative districts: (1) synergistic townships with high GDL and improved EEQ; (2) mismatched townships; and (3) underdeveloped townships with low GDL and degraded EEQ. Although uncertainties remain due to cross-scale data integration and dependence on baselines, this study offers a useful approach to support targeted green development and environmental management in urban agglomerations.