Suppose they cannot maintain physical distancing of at least one meter (3 ft). In that case, people in indoor locations — including children and students aged 12 or over — should also wear a mask even if the spaces are well ventilated.
They should also wear masks outdoors if physical distancing cannot be maintained, it said.
WHO spokeswoman Margaret Harris said the recommendations were among the biggest changes to its guidance on mask-wearing and updated June advice.
“If indoors, unless ventilation has been assessed to be adequate, WHO advises that the general public should wear a non-medical mask, regardless of whether physical distancing of at least 1 meter can be maintained,” the WHO said.
It also advised “universal masking” in all health care facilities, including in common areas such as cafeterias and staff rooms.