LHASA, Oct. 19 (Xinhua) -- The 1,300-year-old Potala Palace in Lhasa, capital of southwest China's Tibet Autonomous Region, has been undergoing its annual facelift since Wednesday.

Around 500 workers, local residents and volunteers will spend a dozen days to whitewash the exterior of the palace, according to Dawa Ngodrup, director of the maintenance department of the palace.

They painted the walls with a traditional formula of milk, honey, sugar and lime, which has a distinctive sweet smell.

"This year, fresh milk was used instead of long-life milk and the proportion of milk and sugar was reduced compared to in previous years to prevent the painting material from going mouldy," said Jorden, deputy director of the administration of the palace.

Ngawang Sangpo, a Lhasa resident, who has participated in the annual whitewashing for over 10 years, said: "It is an act of kindness."

The Potala Palace was built by Tibetan King Songtsa Gambo in the seventh century and expanded in the 17th century by the Dalai Lama. It received 1.45 million tourists in 2017. The palace was included on the UNESCO World Heritage List in 1994.