Significant disparities in urban sustainability among provincial capital cities in mainland China toward sustainable development goal 11

A comparable assessment of urban sustainability across regions provides critical insights for achieving multiple Sustainable Development Goals (SDGs), while it is often constrained by limited indicator data and the lack of comprehensive evaluation methods. This study developed a set of new evaluation indicators to evaluate urban sustainable development in 31 provincial capital cities in mainland China based on statistical data, Earth observation (EO) and geospatial data generated from deep learning and spatial analysis models in line with the urban sustainable development goal (SDG11) with indicator weighing model considering inter-indicator coupling effects. Significant disparities in sustainable development index (SDI) were revealed across economic regions and city types. Regionally, mean SDI was moderately higher in the northeastern (77.83) and eastern (77.34) regions than in the western (76.07) and central (73.14) regions. In contrast, disparities across city types were more pronounced, with Type I and II large cities achieving the highest SDI (84.60 and 82.15), followed by medium-sized cities (80.56), megacities (76.00), and super cities (72.43). Marked within-group heterogeneity was also observed in the western and central regions and across super cities, Type I large cities, and megacities, primarily associated with uneven economic development and disparities in urban living environments. To enhance the sustainability of low value cities and bridge the gap with leading cities, targeted and actionable guidance was proposed to inform policies aimed at advancing urban sustainability. These results provide a reliable scheme for tracking SDG11 progress, enabling policymakers to identify priorities and tailor interventions for urban sustainable development.