Japan's Emperor Naruhito has visited a facility for Indonesia's first subway system, which was built with support from Japan.

The Emperor visited the railway facility in Jakarta on Sunday, the second day of a week-long official trip to the country.

After putting on a safety helmet, he watched workers overhaul train cars. Extensive checks are conducted every few years. Workers separate train bodies from their undercarriage to inspect all parts.

Officials briefed the Emperor on the process. He asked about hardships encountered during the coronavirus pandemic, as well as measures taken to help women and people with disabilities.

He also entered a driver's cabin and asked a female driver what made her decide to do such work.

Indonesia's first subway began operating in 2019, supported by Japanese technological cooperation and a yen loan. The line extends about 16 kilometers, connecting the center of the capital with southern areas.

Construction is underway to extend the system to the north. The expansion is expected to help ease traffic congestion in Jakarta, where conditions are said to be among the world's worst.

The Emperor and Empress Masako are scheduled to meet Indonesian President Joko Widodo and his wife and attend a luncheon on Monday.

The Imperial Household Agency said the Empress refrained from visiting the subway facility to take care of her health.