Over 66,000 stolen cultural relics were recovered in China last year, the National Cultural Heritage Administration announced on April 11.

Around 3,000 cases related to the theft and illegal excavation of relics were solved in 2021, and 650 gangs were caught during the campaign launched by the administration and Ministry of Public Security to fight such crimes.

Of the 62 main suspects in cultural relic-related cases on the country's top-tier wanted list, released by the Ministry of Public Security, all but one had been arrested by the end of last year.

"Cultural heritage administrations and public security departments at various levels of government have closely cooperated to evaluate security conditions and investigate major cases," said Song Xinchao, deputy director of the national administration.

"This powerful campaign safeguarding cultural relics will remain a deterrence for criminals and support future reform in the cultural heritage circle," Song said.

A lost volume of a Tang Dynasty (618-907) Buddhist sutra and six other precious ancient books, which were stolen from Sichuan Provincial Library in Chengdu in 2004, were retrieved from an auction house last year after continuous searches.

In Hangzhou, capital of Zhejiang province, a robbery of the mausoleum of Qian Liu－the founding monarch of the regional kingdom of Wuyue in the early 10th century－shocked the public in 2020. Last year, the two tomb robbers were arrested and sentenced to life imprisonment. All 175 stolen relics from the mausoleum were recovered.

Tomb robbery is among the most common type of cultural relic-related cases, but the battle to defend heritage expands to a much wider theater.

For example, in Zhangzhou, Fujian province, 19 people suspected to have stolen relics from an ancient shipwreck were arrested last year. Over 800 precious works of celadon pottery from the Yuan Dynasty (1271-1368) were retrieved.

China's latest rules overseeing underwater cultural heritage came into effect on April 1.

"Potential hazards threatening the safety of cultural relics are still common," Song said. "Our mission remains challenging."

New technologies like satellite remote sensing, drones and big data analysis are being used to monitor violations against cultural relics.

In 2021, remote sensing was used by the national administration to monitor over 70 key heritage sites in Hebei, Hainan, Shaanxi and Qinghai provinces, and the Guangxi Zhuang autonomous region, and 158 pieces of evidence related to violations, including mismanagement by administrators, were detected.

Smart monitoring systems are also being adopted by cultural heritage departments. Drones are being used to patrol cultural heritage sites in provinces such as Shanxi, Henan and Zhejiang. In the Inner Mongolia autonomous region, all 103 county-level administrative regions use drone patrols for relics.

"Technology can make up for a lack of personnel in charge of supervision," Song explained.

Fire is another major threat to cultural heritage sites in China, many of which are made of wood.

Over 350 fire-prevention projects were being implemented at key sites across China last year. Six cases of fire at cultural heritage sites were reported last year, a sharp drop from 15 in 2020.