Understanding the effectiveness of urban greenspace policies is conducive to the reasonable planning, construction, and management of urban human settlements, which is helpful for achieving climate resilience and spatial equity, yet empirical evidence from rapidly urbanizing contexts in the developing countries remains limited. Using panel data for 33 cities in Jiangsu Province from 2010 to 2023, this study applies a staggered difference-in-differences design to estimate the causal effect of China’s Ecological Garden City (EGC) policy on urban greenspace development. A composite index is constructed to capture multidimensional greenspace outcomes. The results show that the EGC policy improves overall greenspace development and increases the Comprehensive Index of Greenspace Development by 0.032. Among specific dimensions, it significantly increased total green coverage area by 693.3 ha and the number of parks by 9.9, while effects on some structural indicators were not statistically significant. Event-study estimates indicate that the policy effect strengthens over time, while heterogeneity analysis shows stronger effects in prefecture-level cities than in county-level cities. Drawing on institutional isomorphism theory, the study finds stronger support for a coercive mechanism.
Hu et al. (2026) studied this question.