Many studies have found and confirmed the effect of HSR in reducing air pollution including carbon emissions (Lin et al., 2021), particulate matter (Chang et al., 2021), O3 (Guo et al., 2020), NOX (Yang et al., 2022) and other air pollutants. HSR uses fewer fossil fuels compared to traditional modes of transportation.

The expansion of China's High-Speed Rail (HSR) network, now the largest in the world, has had profound economic, social, and environmental effects. Economically, it has significantly reduced "travel friction" between major urban centers, effectively shrinking the geography of the country and facilitating the movement of labor and capital. This has led to the "corridor effect," where cities located along HSR lines experience increased GDP growth and property value appreciation. Socially, it has made long-distance travel affordable and accessible for hundreds of millions of people, particularly during the "Chunyun" (Lunar New Year) travel rush. It has also promoted regional integration, allowing people to live in smaller, more affordable cities while commuting to Tier 1 hubs like Beijing or Shanghai. Environmentally, the HSR has provided a much lower carbon alternative to domestic aviation and private car travel, significantly reducing the carbon footprint of the nation's transport sector. However, the project has also led to massive debt accumulation for the state-owned China Railway and has occasionally caused the economic "hollowing out" of smaller towns that are bypassed by the main express lines.