The smart watch came to his rescue. Smart watches sell for 1,000 ($140) apiece on average in China. Usually, they allow children to receive certain phone calls and tag their locations. Some advanced devices also enable them to take selfies, join friends in a group chat online and even pay for goods and services.

"It's not an exaggeration to say that nearly all of my classmates own a smart watch. We consider it as an indispensable tool," said Bao.

With the newly affluent young parents in the middle-income group willing to spend on their children's tech needs, sales of personal-tech devices are rising. Also responsible for rising sales is the fact that such gadgets help parents to stay connected with their kids and track the latter's movements. This helps them to deal with anxiety related to kids' safety.

Qin Zetian, a 38-year-old technical engineer at a Shenzhen-based internet-based company, said he does feel somewhat at ease now, having bought a smart watch recently for his 8-year-old daughter, who goes to school on her own.

"Both my wife and I used to feel concerned about the safety of our daughter during her walks to and from her school, even though it's just a 10-minute walk. With a smart watch, we are able to know her exact location always," said Qin.

He said his daughter's smart watch also has an emergency call function that allows the user to just press a button to call the police in case of any unexpected accidents.

"Smartphones remain the best way to communicate. However, providing an expensive smartphone to a child is risky. Kids smart watches are not just communication devices; they also gather a child's exact location and record movements," said Ethan Qi, a senior analyst with Counterpoint.

Up to 71 percent of kids smart watches shipped in 2019 had cellular phone functions. Hence, apart from calling, features like an SOS button for emergency communication, geofencing with SMS alerts on entry and exit, and the ability to hear what is happening next to the child are possible, Qi said.

The COVID-19 pandemic has now prompted a string of smart watch companies to add new functions related to health management to their gadgets. For instance, some watches enable children to measure body temperature in real time.

As COVID-19 led to postponement of the normal school semester, more than 300 million students found themselves pursuing their studies at home. This again turned out to be an opportunity for tech firms.