China’s unfinished buildings have created stranded assets with substantial resource and socioeconomic costs

Over the past four decades, China’s rapid urban expansion has been accompanied by a growing wave of housing supply, while also spawning a rising stock of unfinished building projects (UBPs) with unavoidable socio-environmental consequences. The magnitude and spatial concentration of these UBPs, and the resulting stranded materials, emissions, and investments, however, remain unclear. Here, we inventory 1,779 UBPs across 142 Chinese cities by the end of 2023. UBPs are found to have wasted 485 ± 42 Mt of building materials, raised the real-estate sector’s carbon intensity by 9.6%, and imposed ∼2.6 million disability-adjusted life years (DALYs) of fine particulate matter (PM2.5)-related health burden, causing 347 ± 32 billion USD in economic losses borne mainly by homebuyers, developers, and contractors. Driven by land-financing dependence and aggressive development, UBPs clustered in newly developed suburbs, where they deepen service shortfalls and social inequality. A systemic policy framework is needed to manage these “urban stranded assets” and reduce these non-negligible burdens.