BEIJING — China has finished the on-site investigation of 4,532 cave temples and cliff statues, part of a nationwide effort to examine the conservation of the country's grotto sites, said the National Cultural Heritage Administration (NCHA).

Braving freezing winter temperatures, high altitudes and bad weather, nearly 2,000 researchers in 150 teams have taken part in the survey, said the NCHA, the organizer of the national initiative.

In particular, they have completed surveys of a plethora of small and medium-sized grottoes that are either inaccessible or located in places prone to natural calamities.

A total of 1,366 reports have been generated in the process, according to the NCHA, an important step for compiling a national conservation report in June and formulating a protection plan for the next five years.