Does China’s Low-Carbon City Pilot Policy Enhance Urban Compactness? Evidence from Yangtze River Economic Belt, China

Climate change has become a global challenge that cannot be ignored in the pursuit of development. The implementation of the Low-Carbon City Pilot Policy (LCCPP) represents an approach to addressing environmental issues and promoting sustainable development. Investigating the impact of this policy on urban compactness (UC) is therefore crucial for advancing sustainable development. Using a staggered DID model with panel data from 108 cities in the Yangtze River Economic Belt (YREB) over the period 2008–2023, along with robustness checks and spatial analysis, this study evaluates LCCPP’s impact on UC. The main findings are as follows: (1) The LCCPP has a significant positive effect on UC. (2) The policy enhances UC primarily through two channels: intensifying infrastructure development and promoting green technology innovation. (3) The promoting effect of the LCCPP is stronger in cities located in the upper reaches of the Yangtze River, within urban agglomerations, and in non-resource-dependent cities. (4) The policy reduces UC in neighboring non-pilot cities, leading to an overall decline in regional compactness. This study provides an important reference for exploring pathways toward sustainable development.