Smart City Pilots Empower Corporate Green Innovation in a Manufacturing-Driven Economy

The rise of smart cities as systemic eco-innovations has leveraged advanced digital technologies to support green development and reduce carbon emission intensity in manufacturing. Using data on green technology innovations of A-share listed firms in Shanghai and Shenzhen from 2007 to 2022, this study applies a multi-period difference-in-differences design combined with a double machine learning method to assess how smart city pilot programmes influence enterprises’ low-carbon transitions. We find that (1) Smart city pilot programmes significantly increase the quantity, quality, and independence of green patenting, and these effects remain robust under alternative specifications; (2) mediation analysis shows that the pilots improve enterprise’ access to financial resources and strengthen external digital monitoring, which, in turn, enhances environmental disclosure and stimulates substantive green innovation; and (3) heterogeneity tests reveal that policy effects are strongest in regions with weaker environmental regulation, among firms with lower research and development (R&D) intensity, and in pollution-intensive industries, highlighting the contexts in which smart city initiatives are most effective. These findings provide empirically grounded insights into the contextual effectiveness of the smart city pilot and offer concrete evidence to inform its broader adoption and replication.