Cultural heritage workers will launch a program to restore the frescoes of the 1,600-year-old Arjai Grottoes in North China's Inner Mongolia autonomous region, according to the regional cultural heritage administration.

The work, scheduled to start from later this month, will be undertaken by staff with the cultural heritage institute of China's Dunhuang Academy, and is expected to finish in 2021, according to the administration.

The grottoes, home to nearly 1,000 frescoes related to Tibetan Buddhism, are located on a hill in the grasslands of Otog Banner, Ordos city, along with other ancient structures including temples and palaces.

The structures were put under state-level protection in 2003.

The technicians plan to take digital pictures of the frescoes and then repair them as they have been damaged by time and the environment.