But for most local schools, classes were only expected to resume from May 27, beginning with senior secondary pupils.

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The Education Bureau said it gave at least 53 international and private schools permission to resume classes in stages from Wednesday or Friday this week, while pupils at another 19 return to class next Monday.

Education officials suggested half-day classes to reduce social contact and avoid students having lunch together, but 31 schools have been allowed to hold full-day lessons after implementing special lunch arrangements, such as splitting the break into two sessions for more flexibility.

Among those to resume teaching in classrooms on Wednesday were Harrow International School Hong Kong, Li Po Chun United World College, Nord Anglia International School, and Christian Alliance International School.

At Christian Alliance in Lai Chi Kok, about 1,400 students began to return in three phrases, beginning with pupils in Grade Four to Six on the campus for a half day in the morning, and Grade Nine to 12 in the afternoon.

“We will take every measure we can to make the school safe,” head Richard Vanderpyl said. “But if parents are still uncomfortable, they can keep their children home. We will provide resources for those students.”

To reduce the risk of infection, pupils will sit one metre apart in class, and will not share stationery. The school has also installed new sterilised mats, thermal cameras and hand sanitisers for infection control.

The first lesson was a one-hour session for teachers to explain physical distancing and hygiene rules, and for students to share their experiences of learning at home, Vanderpyl said.

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Students are also required to submit a health and travel declaration, and have their temperature checked daily.

Ayla Ip, a 10-year-old Grade Four student, said she was thrilled to be back. “I'm happy to go back to school because I can see my classmates. I missed them.”

Her father David Ip was also happy. “The school has done a lot to keep the kids safe,” he said.

At United World College, a boarding school in Wu Kai Sha, Form Five pupils returned to campus on Wednesday afternoon. Principal Arnett Edwards said there were no official lessons on Wednesday, but students would update tutors on their progress.

Blended learning will be carried out as about half of their 100 pupils in Form Five were not in Hong Kong. He said students staying in the residential area would have to limit their commuting, while wearing masks at all times was only required in the academic section, but not the residential area.

Edwards said most pupils were aged above 16 and the school trusted their maturity.

“We have actually analysed the risks, for the local students, they would be living on campus, rather than some of our students who can take two hours to travel to a campus … as long as we put the protection measures in campus, we feel that’s the most important,” he said.

Student Shiv Bailur, 17, said resuming face-to-face interactions with his peers was not a problem: “I’m not too worried about anything happening inside the campus. I don’t think I’ll be wearing a mask when I’m in my dorm or going to the gym.”

Ruth Benny, founder of private schools consultancy Top Schools, said some parents were concerned about the realities of implementing social distancing at schools. “It won’t be 100 per cent smooth on day 1, we just need to work towards everyone getting on the same page,” she said.

Meanwhile, Hong Kong’s biggest international school operator, the English Schools Foundation (ESF), welcomes senior students back from Friday, with most pupils returning on Monday.

ESF chief executive Belinda Greer said all pupils would be attending full-day classes, but those in Year 11 or below would be on a shift schedule with “one day in school, the following day through online learning”.

“What it enables us to do is to create enough space at all of our schools for social distancing,” Greer said. “Having only 50 per cent of students in school at any one time gives us plenty of space … to comply with the need for a one-metre distance between the students.”

She added that students would also have lunch in batches during multiple sessions.

Meanwhile, the Chinese Manufacturers’ Association said it would be offering free indoor environmental hygiene quality tests for up to 2,200 kindergartens, primary and secondary schools, with testing taking place as early as this week.