Slipping up
Guidance issued to schools by the central government states class sizes should be limited to fewer than 45 children. However, media reports suggest that in some areas, particularly those with large concentrations of migrant workers, teachers are taking classes of up to 60.
Although the number of students has grown, the standard of facilities often lags behind.
Investment in rural and remote schools "is still the big problem", complained Zhang Jing, deputy principal in charge of student safety at Zhufang village middle school in Jiangxi province.
He said his school has a population of 1,600, yet the size of the canteen is less than 30 square meters, "barely enough for a kitchen", he added.
Zhang Liugang, a teacher at Shangyi Primary School in Zhengzhou, agreed and added: "Some schools are overloaded. When you have that many students in a confined space, you need someone to control traffic (on the stairs)."
Based on countless on-site inspections he carried out, retired professor Zhang Yutang said many schools' stairways are too narrow and are not fitted with anti-slip flooring.
Slipping and tripping are major contributing factors to stampedes, he said, explaining that the risk also increases depending on the number of floors.
"Most (of these accidents) happen when all students are going downstairs for exercises or at the end of the school day," said Zhang. "A real danger spot is the second floor, which where the greatest volume of traffic is.
"The greater the number of floors, the greater the threat to children's safety," he warned, before suggesting the reason school accidents are more common in winter months is because children wear bulkier clothing "and are more clumsy".
At Aksu's No 5 Primary School, which is a four-story building, the stampede started in the corner of a stairwell connecting the second and first floors.
Classes at the school resumed on Tuesday, the same day Huang Sanping, Party secretary of Aksu prefecture, told a press conference that the government will pay the medical expenses for all affected families.
"Your children are our children," said Xinjiang vice-chairman Jin Nuo during a meeting with parents at Aksu's No 1 People's Hospital. "We will do everything to help your injured children."
The pledge was welcome news for the seven children who suffered severe injuries in the stampede.
Among the worst injured was Mailinar, 8, who on Wednesday was still receiving treatment for head and chest trauma in the hospital's intensive care unit.
"The girl is in a stable condition. She is able to speak now," said Jing Haitao, deputy director of Xinjiang People's Hospital emergency center in Urumqi. He was among two batches of head injury specialists sent to Aksu to help the stampede victims.
The other six students - two boys and four girls aged 7 to 10 - were also in stable conditions, said medics.