A deliveryman carries daily necessities at a residential area under closed-off management in Xi'an, Northwest China's Shaanxi Province, December 31, 2021. Xi'an imposed closed-off management for communities and villages on December 23 in an effort to curb the spread of the latest COVID-19 resurgence. (Xinhua/Tao Ming)

The health code system in Xi'an, capital of Northwest China's Shaanxi Province, has gone down again, with many local residents claiming that the system wasn't working normally, as the city's lockdown entered its 13th day on Tuesday.

At 9 am Tuesday, Xi'an started a new round of city-wide nucleic acid testing, but many local residents found that the health code system wasn't working. They couldn't open the health code system app on the phone when they tried to have their QR code scanned before undergoing nucleic acid tests. 

A local resident who preferred to remain anonymous confirmed with the Global Times that he couldn't open his health code at around 9 am, but about one hour later, the system worked again.

Xi'an big data bureau told the media that the traffic volume of the platform was too large, and measures limiting the traffic have been adopted which would gradually open it up. It also called for residents to be patient and wait in lines in an orderly manner.

A hotline working staff from the health code system said the repair work has been finished, suggesting residents delete the app first and then re-download it, and it should be working normally again.

The topic with the hashtag "Xi'an health code system" gained over 100 million clicks on China's Twitter-like Sina Weibo as of press time. Some local residents said they've received notices reading that the network of the city's nucleic acid testing emergency platform is busy and now they can't log on due to large traffic, with the system under repair.

It's the second time the city has faced a health code system crash. The system was down on December 20 due to excessive visits.

The health code system in Xi'an should strengthen technical improvement and network expansion to ensure safe and stable operation, said Han Xia, an official of the Ministry of Industry and Information Technology during inspection on epidemic prevention and control work in Shaanxi from December 30 to 31. 

Han asked the working staff to improve the system to ensure no further crashes would occur after the health code system crashed on December 20.

As a city with a population of 13 million and also a transportation hub, the epidemic has impacted many residents. The city has to screen out potential infections and silent carriers before it could lift the lockdown, said Chen Zhijun, deputy director of Xi'an Center for Disease Control and Prevention. The risks of community transmission have to be blocked, Chen noted.