"To comply with the cleaning requirements at Shanghai Pudong International Airport (PVG) that were issued by the Chinese government on December 21, Flight 287 from Seattle to Shanghai returned to (Seattle) while it was en route to (Shanghai), "a company spokesperson said in an email to AFP on Monday.
"The new clean-up procedures require considerably longer floor time and are not operationally viable for Delta," he added without giving details of the procedures in question.
According to Chinese media, several passengers ended up in the United States with expired Covid tests and expired visas, prompting the Chinese consulate in San Francisco to officially complain to Delta.
Thousands of flights have been canceled in recent days by airlines across the world, with many pilots and crews sick or in quarantine due to the highly contagious Omicron variant of Covid-19.
Many authorities have also tightened the restrictions, the Chinese authorities being particularly on the teeth as the Beijing Olympics approach, which begins in less than 40 days.
© 2021 AFP