Assessing Urban Sustainability Using a Multi-Scale, Theme-Based Indicator Framework: A Case Study of the Yangtze River Delta Region, China

Urban sustainability is a great concern worldwide. However, how to evaluate urban sustainability is still a big challenge because sustainable development is multifaceted and scale dependent, which demands various assessment methods and indicators that often do not reach a consensus. In this study, we assessed urban sustainability of the Yangtze River Delta (YRD), China during 2000-2014 at two spatial scales (corresponding to the administrative levels of province and prefecture). A theme-based indicator framework, cluster analysis and Mann-Kendall test were used for urban sustainability assessment. Our results showed that the overall (OS), social (SS), and economic sustainability (EcS) scores for two provinces and sixteen prefectural cities increased from 2000 to 2014 in general, but the environmental sustainability (EnS) scores decreased over time. According to the performance of SS, EnS and EcS at the prefectural level, three distinct city clusters were identified: Cluster 1 with high SS and EcS but low EnS; Cluster 2 with low SS and EcS but high EnS; and Cluster 3 with moderate SS, EnS and EcS. The three sustainability dimensionssociety, environment and economyall changed over time and differed among cities at the two administrative levels. Our results implied that, according to the strong sustainability perspective, the cities of the YRD became less sustainable or unsustainable because the social and economic progresses were at the expense of the environment. The level of urban sustainability was lower at the provincial level than the prefectural level, implying that the problems of unsustainability are even greater at the provincial level than the prefectural level in the YRD region.