China may adopt a flexible working hours system and suspend school classes during high air pollution alerts, according to a government circular issued on November 6.

The circular was released by the Ministry of Environmental Protection as China faces growing pressure to curb air pollution, with heavy smog frequently smothering large cities.

The ministry urged every possible compulsory measure that could reduce emissions to be implemented when the highest alert of air pollution is issued. These measures include suspension or limiting of business production, restriction of vehicles allowed on the road, dust controls and a ban on outdoor barbecues.

Large-scale outdoor activities should also be canceled, and middle and primary schools, as well as kindergartens, should suspend classes, according to the document. Enterprises and institutions are also encouraged to adopt flexible working hours.

The circular also called for the setting of strict controls on coal-fired pollution while encouraging the use of natural gas.