With the acceleration of urbanization and industrialization, the issues of urban pollution emissions and carbon emissions have become increasingly prominent. The coupling coordination relationship between pollution emissions and carbon emissions has also become a key issue affecting sustainable urban development. This paper, based on a systems coupling perspective and social network analysis methods, examines the spatiotemporal characteristics and driving mechanisms of the coupling coordination between pollution emissions and carbon emissions in China. The findings that: (1) There are significant regional differences in the coupling coordination degree (CCD) of pollution and carbon emissions across various regions in China, exhibiting a gradient decreasing trend. The overall national improvement in coupling coordination is limited, indicating a need to strengthen synergistic governance of pollution reduction and carbon emission reduction. (2) The CCD between cities has undergone phased development from ‘barely coordinated—primary coordination—intermediate coordination’, with most cities still at the primary coordination stage. The central and western regions have yet to reach a more advanced coordination state. (3) Analysis of the driving mechanisms indicates that various complex factors, such as economic development, industrial structure, environmental regulation, and green technological innovation, significantly influence coupling coordination.

This paper analyzes the intrinsic relationship between urban innovation capability and inter-city collaborative innovation, utilizing panel data for 76 cities within China’s Yangtze River Economic Belt covering the period 2005–2021. The results indicate that as a city’s innovation capability strengthens, the level of collaborative innovation among them significantly increases. This positive effect operates through promoting the flow of innovative elements, enhancing knowledge spillovers, and fostering technological complementarity. Further analysis reveals that high-speed rail connectivity, supportive government innovation policies, and higher city administrative levels significantly reinforce this positive relationship. While enterprises currently dominate inter-city collaboration, significant potential remains for collaborations involving enterprises and governments, research institutions, and universities. Furthermore, our analysis confirms that innovation capability has a positive spatial spillover effect on inter-city collaborative innovation. Heterogeneity analyses reveal that enhancing urban innovation capability selectively promotes substantive collaborative innovation while inhibiting non-substantive forms, and this positive promoting effect is particularly pronounced within technology-intensive industries. This research offers new perspectives on the capability-collaboration linkage within a major economic region, providing empirically grounded support for implementing innovation-driven development strategies.

The uneven proliferation of artificial intelligence (AI) presents unexamined challenges to sustainable regional development. This study provides robust empirical evidence on how the inter-city AI gap influences environmental dynamics, specifically via transboundary air pollution. Using a framework based on the Technological Gap Theory, the results demonstrate that a wider AI gap significantly intensifies air pollution transmission between cities. The primary mechanisms are widening disparities in digital infrastructure and imbalanced flows of capital and labor. This effect is context-dependent and most severe for economically underdeveloped cities, creating a new form of environmental inequity. The analysis further reveals that while environmental regulations can mitigate this negative impact, technology-centric policies lacking green synergy may amplify it. The research’s findings offer a new theoretical lens on techno-environmental inequality and underscore the necessity of synergistic policies that simultaneously bridge the digital and environmental divides to foster equitable and sustainable development.