WestJet Airlines said on Thursday it had denied 10 passengers from boarding a flight for lacking the proper test for the novel coronavirus, just after a Canadian government requirement that passengers show proof of a negative result before boarding took effect.

Faced with a mounting second wave of infections, Canadian Transport Minister Marc Garneau said last week that air travelers aged 5 and up would need to test negative for the coronavirus before boarding the plane, starting on Jan. 7.

The global airline industry has been calling for COVID-19 testing as a way to ease travel restrictions and reopen borders without crippling quarantine measures, although Canada still requires international passengers to self-isolate for 14 days.

News of the surprise Canadian measure left airlines fearful of possible confusion over which testing facilities abroad for the coronavirus were eligible and how the results from the PCR (polymerase chain reaction) test must be presented to carriers.

WestJet said on Thursday it could not board the passengers because they did not have eligible tests to meet the new government requirement.

Garneau’s office was not immediately available for comment.

A WestJet spokeswoman said by email the carrier has rebooked the passengers denied boarding on the Thursday morning flight from Cancun to Calgary, but said the “situation further highlights the challenges travellers and our operations are facing” from the new requirements.

-This latest announcement by the federal government is specifically the type of chaotic situation WestJet has been seeking to avoid- spokeswoman Morgan Bell said.

As of Wednesday, Canada had reported an additional 8,153 coronavirus cases and 136 deaths.

The International Air Transport Association (IATA) recently called Canada’s decision to mandate a negative COVID-19 test within 72 hours of flying to the country, while leaving in place existing travel restrictions and quarantine requirements, the “worst of both worlds.”