The power of informal regulation: An evolutionary game and empirical analysis of public concern on regional green innovation

This paper investigates whether public environmental concern, acting as an informal regulatory pressure, drives regional green technological innovation (GTI) in China. We develop an evolutionary game model of public–innovator interactions to formalize the coordinating role of public pressure in green investment. Leveraging city-level Baidu search data for “PM2.5” from 2011 to 2019 across 289 cities as a proxy for public attention to pollution, we employ an instrumental variable (2SLS) strategy to identify the causal impact on green patent applications. We find that heightened public concern significantly promotes regional GTI; our estimates suggest that a 1 % increase in the public concern index causally increases green patent applications by approximately 2.1 %. Our analysis further uncovers two key transmission channels: an indirect public channel, where citizen concern stimulates increased government investment in environmental governance, and a direct private channel, where public pressure drives private green investment through reputational and market mechanisms. The innovation-promoting effect of public concern is also context-dependent, proving significantly stronger in cities with greater economic capacity, higher baseline levels of pollution, and more developed information environments. These findings highlight the tangible role of public attention in fostering environmental innovation and underscore the distinct yet complementary roles of state responsiveness and market-based mechanisms in a green transition.