At least 49 passengers on a flight from New Delhi to Hong Kong have tested positive for COVID-19, authorities said, as the financial hub introduced an emergency ban on all flights from India as it battles a new wave of cases.

All of the passengers who tested positive flew into Hong Kong on a flight run by Indian operator Vistara on Apr 4.

The positive tests are significant as Hong Kong is regularly recording fewer daily cases than the total detected on the flight since it brought a fourth wave under control in January.

Authorities imposed a two-week ban on all flights from India, Pakistan and the Philippines from Monday (Apr 19), categorising the countries as “extremely high risk” after detecting the N501Y mutant Covid-19 strain for the first time.

India is battling skyrocketing infections, with hospitals running out of beds and the government forced to reimpose economically painful restrictions.

Its capital New Delhi went into lockdown from Monday night as officials scramble to get surging cases under control.