BEIJING, China (Xinhua) – Beijing’s municipal emergency response headquarters issued an orange alert for heavy air pollution on Thursday evening — only two days after a red alert was lifted — and told residents to wear masks or stay indoors.

Roughly 50 cities in northern and eastern China have issued air pollution alerts recently. Beijing educational authorities on Friday morning sent a message to schools telling them to make their own decision to cancel classes or not.

Some schools took a day off, others stuck to the schedule. Some were reluctant to sound any alarm at all and left it up to individual parents. Some teachers went to school to support students who had chosen to brave the murk and attend class.

“I was already en route to school when I heard about the suspension and had to turn around,” said one parent, wondering why the school did not send the message earlier.

Schools should be granted discretion to suspend class in bad weather instead of waiting for the official alert, said Xiong Bingqi, deputy director of 21st Century Education Research Institute.

While some students were happy to skip school, others saw little to celebrate. Some parents also worried their kids may fall behind if they miss several days of lessons.

Though schools told students to join online classes on their own, many parents were concerned that their children were without proper guidance and supervision from either teachers or themselves.

Britain allows parents to suspend work in emergency circumstances to look after or tutor their children at home, and China should follow that example, said Luo Zhimin, an educational professor with Yunnan University.

Schools and administrations need an overall plan, including early warnings, a flexible syllabus, and better communication with teachers and parents, Xiong said.