Flight operations at Hazrat Shahjalal International Airport (HSIA) were suspended for nine hours from 12:15am yesterday due to dense fog, resulting in the delay of at least 30 international and domestic flights.

Poor runway visibility forced the airport authorities to stop both inbound and outbound flight operations, said the Station Air Traffic Control (SATC) officer.

He said the fog was too heavy for flight operations after midnight. "The operations had resumed right after the fog began to clear," he added.

"The flight operations resumed for domestic flights at 9:30am and international flights at 10:15am this [yesterday] morning," Public Relations Officer of Civil Aviation Authority of Bangladesh AKM Rezaul Karim told The Daily Star.

Due to the fog, six passenger flights and one cargo aircraft were diverted to other airports including the ones in Kolkata and Chittagong.

A Thai Airways flight was forced to return to Bangkok after failing to land at HSIA. It was scheduled to land at 12:40am. A Saudia flight scheduled to land at HSIA at 12:55am was diverted to Kolkata.

A Unitop cargo aircraft from China was diverted to Myanmar around 12:50am. A Gulf Air flight was diverted to Kolkata around 4:00am and a US-Bangla flight was diverted to Chittagong, he added.

Besides these, departing flights of Biman Bangladesh Airlines, China Southern, Emirates, Malindo Air, Qatar Airways and Air Asia were delayed for several hours. Those flights departed after 10:15am, Karim said.

Apart from international flights, one Biman Bangladesh Airlines, four Novo Air and three US-Bangla Airlines domestic flights were also delayed.