Harmonizing new-type urbanization and eco-efficiency: spatial–temporal coupling coordination in the Yangtze River Economic Belt

The Yangtze River Economic Belt (YREB) plays a crucial role in addressing China’s dual challenges of rapid urbanization and environmental sustainability, while also serving as a significant hub in the global economy due to its strategic importance in trade and innovation. This study investigates the dynamic relationship between new-type urbanization (NTU) and eco-efficiency (EE) within the YREB from 2010 to 2020. Utilizing the entropy method and the Super-SBM model, we assess the NTU index and EE across multiple cities, subsequently analyzing their interactions through the coupling coordination degree (CCD) model. Our findings reveal an overall upward trend in both NTU and EE. Specifically, the average CCD increased from 0.52 to 0.68, indicating a transition from “running-in and basic coordination” to “highly coupling and good coordination”. Despite this progress, the Moran index reveals persistent spatial heterogeneity, with the presence of high-high (HH) clusters in the Yangtze River Delta reflected strong synergies in 2010, but by 2020, their range narrowed, with new low-low (LL) clusters in Anhui and high-low (HL) outliers in the west, underscoring regional policy needs. Furthermore, we identify three distinct sub-types of coupling coordination—systematically balanced, NTU lagging, and EE lagging—which highlight the necessity for tailored regional policies. These results underscore the critical importance of developing region-specific strategies to harmonize urban growth with ecological sustainability, thereby contributing to broader sustainable development objectives within the YREB and beyond. © The Author(s), under exclusive licence to Springer Nature B.V. 2025.