China has made marked progress in shifting more freight transport from road to railways, as the country forges ahead to enhance management over diesel-powered trucks, a major contributor of air pollutants.

Following continuous growth since 2017, the freight amount transported via railway in the country in 2020 reached about 4.5 billion metric tons, sad Liu Youbin, spokesman with the Ministry of Ecology and Environment, in a news conference on Monday.

Even more robust growth has been registered this year. With a year-on-year increase of 13.5 percent, the railway system helped transport almost 2 billion tons of freight from January to May, he added.

He said the achievement was thanks to a series of measures the ministry has taken to curb road transportation, which is a key part of its efforts to enhance air pollution control.

Most trucks used for freight transportation in China are diesel-powered. Such trucks contribute the most PM 2.5 particulate matter from motorized vehicles in Beijing, according to an analysis of PM 2.5 sources by the Beijing environmental authority in 2018.

Liu said during days with heavy air pollution, for example, the ministry has spared companies that do well in promoting railway transportation from suspending operations under an emergency response system.

The ministry has also introduced preferential policies to support the development of companies that turn to railway to transport their freight, he continued.

He said the country saw 81 railway lines that serve certain companies' freight transportation needs completed or go into operation in 2020. While 53 have been completed or opened for business so far this year, another 165 are under construction.