Several schools in northern China, one of the most polluted parts of the world, are installing huge domes where children can play and exercise during recess to protect them from the smog outside.
The domes resemble inflatable greenhouses and are as big as a stadium, 50m long, 20m wide and 10m , said the Global Times daily.
The domes, manufactured by MetaSpace Air Dome Corp, a Beijing-based company, uses filtration systems to keep the air inside pollution-free.
Dozens of cities in central and northern China have been witnessing levels of polluting particles of over 500 micrograms per cubic metre, five times above the acceptable level, but inside the domes this level is less than 10.
The popularity of the domes increased a few weeks after a school in the city of Linqi in the northern Henan province hit the headlines for making its students take an exam in the playground amid heavy smog.
Images of the children, seated at their desks amid a thick cloud of smog, shook the world and led to the principal of the school, Feng Jisheng, being sacked.
Persistent smog in cities, including Beijing and Tianjin, has sparked alarm among the people of northern China, who are concerned about the long-term effects of the pollution on health.
In Beijing, parents of students have been asking schools to install air purifiers in classrooms, a demand the capital's Education Commission accepted yesterday.