Almost 80 percent of primary and secondary school students had the opportunity to get more nightly sleep this semester, after education authorities took measures to reduce their academic workload, the Ministry of Education said on Dec 22.

Lyu Yugang, director of the ministry's department of basic education, said 77.14 million parents were surveyed to ascertain whether their children were getting enough sleep. A total of 76.2 percent of respondents said their children were getting the recommended sleep time of 10 hours a night for primary school students and nine hours for those in secondary school. Last year's survey found only about 40 percent of students were getting enough sleep, Lyu said.

Schools and parents have also paid more attention to students' sleep time, with 98.7 percent of schools asking parents to monitor their children's sleep and study time.

In April, the ministry advised that primary school students should go to bed before 9:20 pm, middle school students before 10 pm and high school students before 11 pm.

Students should go to bed at the recommended times, even if they have not finished their homework, the ministry said.

Schools should control the amount of homework assigned to students to make sure primary school students can finish all their written homework at school and secondary school students can finish most of their homework on campus, the ministry said.

"Homework, after-school tutoring courses and online games should all take second place to ensure students can get sufficient sleep," Lyu said.

The ministry also issued recommendations in April to cease starting classes too early. A total of 96.1 percent of primary schools now start classes at 8:20 am, and 97.4 percent of secondary schools start at 8 am or later, Lyu added.

Separately, 99.8 percent of primary and secondary schools have issued rules preventing students from bringing smartphones to class and provided communication channels for students to contact their parents in an emergency, he said.

Almost all schools no longer assign homework via smartphones and students do not need to finish their homework digitally, he added.

Ye Yuyu, mother of a second-grade pupil in Beijing, said the school basically assigns no written homework to her daughter and she can sleep more than 10 hours every night.

"We believe a healthy body is more important than academic achievement," she said.

However, Ye said she assigns some homework to her daughter so that she can still practice what she has learned at school.

Zhang Xiu, mother of a middle school student in Beijing, said her daughter can sleep more than nine hours a night, as the school has reduced the amount of her homework.

Her daughter can finish her homework before 8 pm and usually goes to bed before 9:30 pm, Zhang said.

Luo Lin, vice-principal of Fengtai Experimental School Affiliated to Beijing Institute of Education, said some students go to bed late not because they have heavy academic burdens, but because they are following the examples of their parents who stay up late and spend a lot of time on their smartphones.

Parents need to assume the main responsibility to ensure their children get enough sleep, Lyu said.

While tough measures have been taken to limit the amount of time young students can spend playing online games to three hours a week, the students might waste time on short video platforms and parents need to act to prevent this, he added.