Like most major carriers, KLM has grounded almost all its airplanes due to the coronavirus pandemic, but is still operating a small number of flights.

“Wearing facial protection during boarding and on board is mandatory for KLM passengers. Passengers must ensure that they carry the required facial protection with them,” KLM said. Passengers without adequate facial protection may be refused boarding at the gate, it added.

The measure applies until 31 August 2020. Children under 10 years of age are exempt.

The International Air Transport Association (IATA), the body representing global airlines, has come out in favour of passengers wearing masks onboard, as debate intensifies over how to get airlines flying while respecting social-distancing rules following the coronavirus crisis.

Air France, the French subsidiary of Air France KLM, announced the same safety precautions on May 5, while Germany’s Lufthansa (LHAG.DE) and Hungary’s low cost Wizz Air (WIZZ.L) are among other European airlines to already have made it compulsory to wear face masks on flights.