HONG KONG — A row has erupted on Chinese social media over the use of air conditioners in classrooms as the country endures an unseasonal heatwave.

Parents in some of China's hottest cities have called on schools to install air conditioners as temperatures surpass 35C.

The conversation heated up in the southern city of Changsha where the education department responded saying it will not install air cons so students can "cultivate the spirit of hard work and endurance".

The comment drew outrage online, sparking a debate on who should pay for the air conditioners and whether they should be used at all.

"Hard work and endurance? Can we please then ask the education bureau to work in 40-degree heat, then discuss whether this is the way to cultivate such spirit in children," wrote one Weibo user.

Another wrote: "Global warming has become so serious. What do you want the children to do?"

Most classrooms in China do not have air conditioners and rely on ceiling fans instead.

But calls to install them have intensified in recent months.

“Without air conditioning, it would be challenging to concentrate on studying,” Lin Yujun, the father of a junior high school student in Guangdong in southern China told Sixth Tone.

Not all parents are in favor of installing air conditioners. Some have voiced concern about the higher risk of catching a cold or other infections at school in air-conditioned classrooms. Others have suggested changes to the school calendar.

“It was never so hot in September in previous years. Perhaps the education board can extend school holidays, according to the weather,” a parent told CQ News in Chongqing.

Earlier this year, China's weather bureau warned of hotter and longer heatwaves, adding that maximum temperatures across the country could rise by up to 2.8 degrees Celsius within the next 30 years.

Schools, however, are reluctant to commit to the steep cost - of the aircons and the electricity bills that would follow.

A primary school in the southern city of Xiangtan drew criticism for asking parents to pay for the air conditioners - the school invited them to donate, reported Sixth Tone, a Shanghai-based news site.

The local education bureau later ordered the school to reimburse the parents.

But comments online supported the school's request as reasonable, saying that students' comfort should be the priority.

"Now that [authorities] have stopped parents from contributing, when will school students be able to use air conditioners under such persistently high temperatures," wrote Long Zhi Zhu, a commentator for local media outlet The Paper.

"[Everyone] has been going around in circles on this issue. Ultimately, the children are the ones who suffer," wrote a Weibo user.

Some schools are trying to cope with the heat without the help of air conditioning - they have taken to placing buckets with large blocks of ice inside classrooms to cool the space down.

Some schools in the eastern Jiangxi province and the south-western Sichuan province postponed the start of the autumn semester, due to begin on 2 September, by a week. — BBC