The southern Chinese city of Shenzhen has launched a facial recognition system for entry to its subway system, joining a number of other centres throughout the country embracing the technology.
People over the age of 60 can register for the system for free entry at some subway entrances, state news agency Xinhua reported on Sunday.
This technology has been developed by the metro operator and internet giant Tencent, and will gradually be extended to allow free entry to other sections of the community, including military veterans.
For now, the service is only available at the 18 stations on Line 11, and involves 28 automatic gate machines and 60 self-service ticket processors.
The city has also been experimenting with facial recognition payment technology in the subway, with a test ticketing system installed in Futian station in March.
Instead of using cash or scanning a QR code on their mobile phones to pay for a ticket, commuters can have their face scanned and the fare deducted from a registered account.
Similar technology is also operating in other cities, including Jinan in the eastern province of Shandong, where the system has been up and running since April.
About 500 commuters use the facial recognition technology to pay for tickets each day in Jinan, according to Chinese media reports.
In Guangzhou, in southern China's Guangdong province, the machines were installed in two subway stations as an experiment on September 10.
In all, about 10 cities, including Shanghai, Qingdao, Nanjing and Nanning, are using the systems on an experimental basis, according to a report released last month by an institution affiliated with the China Information Industry Trade Association, a national level non-profit organisation.
The use of such payment services is another step in the country's drive to integrate technology-based on facial recognition and other forms of artificial intelligence into everyday life.
According to Chinese media reports, AI has been used to scan crowds at events such as pop concerts, helping police to spot and then arrest a number of wanted suspects.
But there are public concerns about the security of people's data.
In a report published in January about mobile payments by the Payment and Clearing Association of China, 85 per cent of respondents surveyed in 2018 said they were willing to use biometric systems for payments, a slight increase from 2017. However, 73.8 per cent of respondents said they worried about leaks of personal data - although that was down from 84.8 per cent a year earlier.
Other countries are also deploying facial recognition systems, including India which is reportedly aiming to build one of the world's biggest.
The government of Indian Prime Minister Narendra Modi will open bids next month to build a system to centralise facial recognition data captured through surveillance cameras across the country.
It would link up with databases containing records for everything from passports to fingerprints to help India's police force identify criminals, missing people and dead bodies, Bloomberg reported.
This article was first published in South China Morning Post.