Sitting at the entrance of Chengdu's East Railway Station, Fu Guobin stared at a screen displaying infrared images of people passing through the station's gates. As each person entered, a number popped up next to their image indicating their body temperature."This is making my life much easier," the station employee said as he sat in his booth. "Before this, I'd have to test everyone's temperature with an ear thermometer. And sometimes that doesn't work - I think this new system is much better."With more than 50 000 people passing daily through the railway station where Fu works, there is enormous pressure to swiftly and accurately identify those who may have a fever - one of the main symptoms of the new coronavirus infection that has killed 2870 people in mainland China.The thermal scanners - newly installed at train stations in major Chinese cities - are just one of the ways in which authorities are using artificial intelligence (AI) and big data to combat the deadly virus, which has now reached 56 other countries since it was first detected in central China's Hubei province in late December 2019.Fu said so far there's only been one instance where he's had to inform health officials about a passenger, a woman from Henan whose fever stood at 37.9 degrees Celcius."After a few minutes, her temperature still hadn't dropped. We have an isolation room in our railway station, so we put her in the room and took down her travel information, and then alerted the health authorities," he said.If she did carry the virus, the hospital would inform transport authorities, who would in turn alert every single passenger in her wagon, according to Fu. The authorities can do this because they keep track of every passenger via rules that require people to use their real names to use public transport. Now, some companies in China are planning to upgrade the temperature detection system to include facial recognition technology. On February 7, AI company Megvii said it was working on a solution that "integrates body detection, face detection and dual sensing via infrared cameras and visible light" to help staff working at airports and train stations "to swiftly identify people who have elevated body temperatures".The company was responding to a call by Chinese authorities for new technologies to combat the outbreak."Facial recognition and the real-name system will help us track down those who have potentially been exposed to the virus and effectively curb the spreading of the pathogen," Zeng Yixin, deputy director of China's National Health Commission, told reporters on January 26."This high level of technology was not available during the SARS outbreak in 2003," he said, referring to another viral outbreak that killed hundreds of people in China. "So we believe the technological development is on our side in battling this outbreak."The Chinese government has arguably set up the most expansive and sophisticated surveillance system in the world. In addition to the real-name system - which requires people to use government-issued ID cards to buy mobile sims, obtain social media accounts, take a train, board a plane, or even buy groceries - authorities also track people using some 200 million security cameras installed nationwide.Some of these cameras are equipped with facial recognition technology, allowing authorities to track criminal acts, including offences as minor as jaywalking. There are reports authorities are using this extensive surveillance system to keep tabs on people amid the coronavirus outbreak.Ren, a restaurant owner who works in Hubei, the province at the centre of the epidemic, said local police showed up at his home in western Sichuan province where he had returned for the Chinese New Year celebrations on January 23 and ordered him to quarantine himself for 14 days. That was the same day authorities placed Hubei under an unprecedented lockdown to prevent the spread of the virus.The police took down his number and said they would call every day to check his temperature. The following day, Ren, who asked to be identified only by his surname, went to a nearby farm to harvest cabbage and radishes for the New Year's eve dinner. As he arrived, he received a phone call from the local authorities telling him to return home immediately.Ren said he believes local officials had tracked his movements using surveillance cameras installed in his neighbourhood."I expected they'd find out I had returned to Sichuan from Hubei because all the trains and buses I took require real-name registration," Ren told Al Jazeera in a phone call. "What I was surprised by was the fact they have surveillance cameras installed in my small neighbourhood, and they might be constantly monitoring to make sure I don't leave my house during the 14-day quarantine."Ren, who said he did not get sick and has now completed the mandatory quarantine, counted at least four CCTV cameras near his house.Other ways in which China is using big data in this outbreak include tracking information on people's movements through their mobile phones and rolling out mobile apps that allow users to find out if they have come in contact with a confirmed coronavirus carrier.For instance, telecom company China Mobile sent numerous text messages to media outlets about people confirmed to have the virus. These text messages normally include information about a patient's travel history and could be as detailed as the seat he or she sat on while taking a specific train or even which subway train compartment they boarded at a specific time. In the early days of the outbreak, media outlets would post this information on social media, allowing people to find out if they had come to close contact with confirmed patients and then quarantine themselves if necessary. The government has now rolled out a mobile app called "Close Contact Detector" to allow people to do this. Upon entry of personal identification details, users can scan a QR code to check whether they have been in close contact with someone infected and whether they are at a heightened risk.Meanwhile, some companies who have summoned their employees back are requiring them to submit a "travel verification report" produced by telecom providers. After sending a message to his or her provider, a user will automatically receive a message that details all the cities they visited in the past 14 days and the recommended quarantine time based on the location-tracking system."We have long believed that big data can help the government effectively forecast the development of a given epidemic, and to do that, we need to integrate the collection of the data in surveillance," said Dr Cecile Viboud, a staff scientist at National Institutes of Health's Division of International Epidemiology and Population Studies in the US. "China has a very comprehensive system of surveillance that has proven helpful in collecting the data needed."This epidemic has given the Chinese government a perfect excuse to drag out its massive surveillance system but such expansive data-collection has also created concerns among people who fear their privacy was severely compromised by this effort."Collecting personal data to control the outbreak should respect 'minimalism rule' and avoid excessive collecting," said Qiu Baochang, a Beijing-based lawyer who focuses on privacy law. "It's incredibly important to make sure no information is leaked and all collected data should be deleted after use."Mu, a resident of Chengdu who preferred to give one name, said: "I understand the rationale behind this decision [to track down possible virus carriers] because of this special situation we're going through. But there has to be a limit - it's becoming increasingly worrying how much information the government has on us."