The Impact of China’s Digital Industrial Cluster Policy on Urban Carbon Quota Development

The digital industrial cluster policy is a key policy instrument for fostering the digital economy and facilitating urban low-carbon transition. Given that no official carbon quota allocation system has yet been established at the city level in China, this paper constructs a multidimensional urban carbon quota index that integrates social, economic, and ecological dimensions, and uses it to measure the carbon quota level of 297 prefecture-level-and-above cities in China over the period 2006–2024. Treating China’s digital industrial cluster policy as a quasi-natural experiment, we employ a staggered difference-in-differences (DID) design to systematically evaluate the policy’s effect on urban carbon quota and the underlying mechanisms. The results show that ① the digital industrial cluster policy significantly raises the urban carbon quota level; ② mechanism tests indicate that this effect is channeled through three paths—stimulating green technological innovation, promoting industrial structure advancement, and improving electricity energy efficiency; ③ heterogeneity analysis reveals that the effect is more pronounced in western regions, in central cities, and in areas with more advanced digital infrastructure and higher carbon quota endowment; ④ spatial econometric results further show that the policy not only enhances local carbon quota but also generates a significant positive spatial spillover effect, raising the carbon quota level of neighboring cities. These findings offer insights for optimizing urban carbon quota allocation through spatial coordination, path coupling, and targeted policy design.