"Crouching inside a police vehicle on a snow-covered mountain, six police in Chongli, the ski competition venue of the 2022 Beijing Winter Olympics, stayed on duty overnight at quarantines at a checkpoint leading to the ski community," wrote officer Liu Haiyan in his work log.

On Jan. 31, police started the round-the-clock duty at the Huapiling checkpoint, Chongli, northern China's Hebei Province.

The area sits 2,128.7 meters above sea level, where it is covered in snow for more than 150 days a year and temperatures in winter dip down to minus 40 degrees Celsius.

Aerial photo taken on Oct. 27, 2019 shows a high-speed train running on the Guanting Lake Bridge section of Beijing-Zhangjiakou high-speed railway in Zhangjiakou, north China's Hebei Province.  (Xinhua/Yang Shiyao)

After three days of keeping watch in cars, a makeshift house was built for the police officers to station there.

"I now fully understand what 'freezing cold' means. It is not the cold that you feel, but pain, pains to numbness and pain to tears coming out unconsciously," Liu said in the diary.

In China's comprehensive prevention and control of the novel coronavirus (COVID-19), the police have been enlisted to safeguard the mountainous sports venue, checking the body temperature of every person passing through.

In January, the number of skiers to Chongli doubled compared with 2019 thanks to the operation of the Beijing-Zhangjiakou high-speed railway since Dec. 30. Chinese athletes also went to the venue for training to prepare for the Beijing 2022 Winter Olympics.

The high-speed railway shortens the intercity travel between Beijing and Zhangjiakou to one hour, making shuttles convenient between the co-host cities of the Olympics. The Zhangjiakou competition zone located at Chongli will host ski and snowboarding events.

However, all skiing activities came to a halt due to the epidemic. Only locals can pass through the checkpoint.

"Some visitors are unaware of the business closure. We are here to inform them, tell them to go back and that it is impassable here," said Liu.

In addition to Chongli, the mountain path also leads to a prairie resort, making it attractive to self-driving travels.

Liu said besides checking body temperatures, their work also includes registering the information of personnel and vehicles passing through and even clearing snow on the roads now and then.

Thanks to the strict quarantine measures, there are zero coronavirus reports in the mountain town.

It takes 30 minutes for the police to go downhill every day to get a supply of drinking water. When the water is carried to the checkpoint, it is covered with ice.

"We change shifts every two hours since no one can stay outdoor longer than that in the freezing cold weather," Liu said.

As more and more people know about their sacrifice, folks send gifts such as hot compress patches and protective suits and goggles to the watchers.  Enditem