Ahead of the arrival of Ragasa, about 80% of the aircraft belonging to the four main airlines based in Hong Kong had been relocated to or grounded at airports in Japan, China, Cambodia, Europe, Australia and other locations, according to Flightradar24 tracking data.

All landings and departures at Hong Kong, the world’s busiest cargo airport and the ninth busiest for international passenger traffic, were cancelled for 36 hours starting on Tuesday evening, reports Reuters.

Hong Kong’s largest airline, Cathay Pacific Airways, said it would cancel over 500 long-haul and regional flights.

“We are positioning some of our aircraft away from Hong Kong and expect a staggered and gradual resumption to our schedule throughout Thursday into Friday,” the airline said.

Hong Kong-based Greater Bay Airlines, a small carrier with seven aircraft, said it had parked all its planes away from Hong Kong as a safety precaution.