Increasing carbon efficiency is a key path to sustainable development, and information and communication technology (ICT) may help realize a win-win situation for the economy and the environment. However, the existing literature on the impact of ICT on carbon efficiency is relatively shallow. Using a database of Chinese cities, this study empirically explores the role of ICT in carbon efficiency from the aspects of direct impact, mediation effect, and threshold effect. Results show that ICT significantly improves the carbon efficiency represented by single-factor and total-factor carbon efficiency. The mediation effect indicates that technological innovation, industrial structure upgrading, and external openness are effective ways for ICT to play its role. The threshold model shows that the promoting effect between the two depends on the local institutional environment. Further heterogeneity analysis shows that ICT plays a more remarkable role in promoting carbon efficiency in eastern regions. This study provides evidence for aggressively digitizing economies to shift towards a low-carbon economy. Policymakers are encouraged to consider better integrating ICTs into sustainable development strategies.

Energy efficiency is the key to green development, and the government plays a vital role in energy efficiency. This paper clarifies the mechanism by which the Yangtze River Delta Economic Coordination Committee affects the energy efficiency of urban agglomeration by promoting market integration. Based on panel data of China's prefecture-level cities from 2004 to 2017, we take the Yangtze River Delta Economic Coordination Committee as a quasi-natural experiment of government cooperation and use the difference-in-difference method to test whether this organization has enhanced the energy efficiency of urban agglomeration. The results show that the Yangtze River Delta Economic Coordination Committee can significantly improve energy efficiency in urban agglomerations. The mechanism analysis shows that it reduces the energy consumption per unit of gross domestic product by enhancing the marketization level, perfecting the relationship between the government and the market, and improving the factor market development. The heterogeneity analysis shows that cities with lower city size, lower level of innovation, and cleaner industrial structures gain more benefits in energy efficiency from government cooperation in urban agglomeration. This paper provides empirical evidence for cities to realize integrated energy conservation through government cooperation and market integration.