Based on the data of 85 cities in the three major urban agglomerations in the Yangtze River Economic Belt from 2011 to 2020, this paper measures the level of high-quality economic development of each city through the improved entropy-weighted TOPSIS method and uses the kernel density estimation method, Dagum Gini coefficient, and convergence model to further study the dynamic evolution, regional differences, and convergence state of the high-quality economic development level of the three major urban agglomerations in the Yangtze River Economic Belt. The study finds that: 1) the high-quality economic development level of each city within the three major urban agglomerations of the Yangtze River Economic Belt has been continuously improved over time, but the development level of each urban agglomeration is not the same; 2) the high-quality economic development level of the three urban agglomerations in the Yangtze River Economic Belt has spatial differences, that is, the high-quality economic development level of the Yangtze River Delta urban agglomeration is better than the two urban agglomerations; 3) the σ convergence and β convergence characteristics exist in the three major urban agglomerations as a whole as well as in each urban agglomeration, and the β convergence rates of the urban agglomerations are not consistent. On the whole, the convergence rate of the middle reaches of the Yangtze River urban agglomeration is the fastest, followed by the Chengdu-Chongqing urban agglomeration, and the Yangtze River Delta urban agglomeration is the slowest. Finally, based on the findings of the study, targeted policy recommendations to promote the high-quality economic development of the three major urban agglomerations in the Yangtze River Economic Belt are proposed.

Low-carbon pilot policies are an important way to achieve the goal of "peak carbon neutrality" and are of great significance to China’s international commitments. Based on a sample of 282 prefecture-level cities from 2006 to 2020, this paper investigates the impact of low-carbon pilot policies on urban carbon efficiency using a quasi-natural experiment with three batches of low-carbon pilot cities in 2010, 2012, and 2017, respectively. It is found that: (1) low-carbon pilot cities can improve urban carbon emission efficiency, which is still valid after a series of robustness tests such as the parallel trend test, placebo test, PSM-DID, and counterfactual test; (2) low-carbon pilot cities can enhance urban carbon emission efficiency by promoting the level of urban innovation and advanced urban industrial structure; and (3) the impact of low-carbon pilot policies on urban carbon emission efficiency is heterogeneous across cities with different geographical locations, population sizes, and resource endowment types. The findings provide policy insights for the promotion of low-carbon pilot policies and strengthening the construction of low-carbon pilot cities.

The development of transportation infrastructure can ensure the strong recovery and reconstruction function of a city, and it is an important way to build a resilient city. Studying the impact of the transportation infrastructure level on urban resilience is related to the future development of a city. Based on panel data for China’s three major urban agglomerations from 2008 to 2019, this paper uses the spatial econometric model to explore the spatial spillover effect of transportation infrastructure on urban resilience. The results show that, due to its spillover effect, intra-regional transportation infrastructure promotes the urban resilience of cities around Beijing–Tianjin–Hebei and the Pearl River Delta, while it only promotes the urban resilience of local cities in the Yangtze River Delta. Inter-regional transportation infrastructure not only inhibits the local urban resilience of Beijing–Tianjin–Hebei but also reduces the urban resilience of surrounding cities. However, the impact on the Yangtze River Delta and the Pearl River Delta is not obvious. To promote the overall resilience level in three major urban agglomerations in China, this paper argues that it is urgently required to improve the quality of urban road traffic facilities and optimize the structure of intercity transportation to promote the development of transportation infrastructure and urban resilience. The implementation of several policies is recommended to efficiently improve the transportation infrastructure and urban resilience in these three major urban agglomerations in China.