Research on the Impact of Digital Infrastructure on Urban Breakthrough Green Innovation: A Case Study of the Yangtze River Economic Belt in China

Breakthrough green innovation acts as a critical leverage point and a fundamental driver of the development of new productive forces. This study employs a sample of 108 cities along the Yangtze River Economic Belt from 2011 to 2021 to investigate the impact of digital infrastructure on urban breakthrough green innovation and its underlying mechanisms. The findings are as follows: (1) Digital infrastructure construction facilitates urban breakthrough green innovation, with a notably more substantial impact on strategic breakthrough green innovation. This result is validated through robustness and endogeneity tests. (2) Heterogeneity analysis indicates that the enhancement effect of digital infrastructure on breakthrough green innovation is more prominent in non-resource-based cities, cities with higher levels of marketisation, and those with weaker environmental regulations, with a particularly significant influence on substantive breakthrough green innovation. (3) Mechanism analysis reveals that upgrading industrial structures, optimising market resource allocation, and increasing public environmental awareness are critical mechanisms through which digital infrastructure strengthens urban breakthrough green innovation capacity. Additionally, as improvements occur in industrial structure, market resource allocation efficiency, and public environmental awareness, the impact of digital infrastructure on urban breakthrough green innovation capacity displays a nonlinear effect.