BEIJING — China opened 39 new rail transit lines in its urban areas in 2020, the country's transport authority said.

The length of these new tracks reached 1,240.3 km, up 20.1 percent from the previous year, bringing the total length of the country's urban rail transit networks to 7,545.5 km, according to the Ministry of Transport.

As of the end of last year, the country had put 233 urban rail transit lines into operation in 44 cities, with a total of 17.59 billion trips made on these lines.

China has vowed to build a modern comprehensive transport system by 2035, noted a white paper titled "Sustainable Development of Transport in China" released by the State Council Information Office.

The system will be safe, convenient, efficient, green and economical, featuring world-class facilities, technologies, management and services, according to the white paper.