Why Does Dhaka Airport's Fog Crisis Force Nine Flight Diversions?

January 2, 2026 at 12:00 AM•3 min read

Dhaka's Hazrat Shahjalal International Airport (HSIA) diverted nine flights to Chattogram, Kolkata, and Bangkok due to dense fog and a lack of an upgraded Category 2 Instrument Landing

Key Points

1Nine flights were diverted from Dhaka's HSIA due to dense fog and poor visibility, impacting operations across South Asia and Southeast Asia.
2The airport operates with a Category 1 Instrument Landing System (ILS), requiring a minimum visibility of 800 metres for landing.
3Aviation experts and safety officials stress that upgrading to ILS Category 2 or 3 is critical to prevent frequent winter disruptions and reduce airline operational costs.
4The inability to maintain the runway lighting system's full functionality has been cited as a reason for the airport's ILS downgrade from Category 2 to Category 1.

Dense fog caused major operational disruption at Hazrat Shahjalal International Airport (HSIA) in Dhaka, leading to the diversion of nine incoming flights. The flights were redirected to alternate airports today due to critically poor visibility.

Four of the diverted flights landed at Chattogram, four were sent to Kolkata, and one was rerouted to Bangkok, Thailand. This incident highlights a recurring challenge for the Dhaka airport flight diversions during the winter season.

The ILS Category Challenge

Aviation experts cite the airport’s current Instrument Landing System (ILS) as the primary cause of these frequent disruptions. HSIA is currently operating with an Instrument Landing System Category 1 (CAT I). This system requires a minimum visibility of 800 metres for safe landing, according to pilots.

ILS is a precision runway aid that uses radio signals and high-intensity lighting. It guides pilots during low-visibility conditions. The International Civil Aviation Organization (ICAO) classifies ILS into three main categories. Category 2 (CAT II) allows for landings with significantly lower visibility, typically between 500 and 750 meters.

Upgrade Status and Operational Impact

Pilots and safety officials have long advocated for an ILS Category 2 upgrade, or ideally Category 3. Upgrading the system would significantly reduce fog-related diversions. The Civil Aviation Authority of Bangladesh (CAAB) has acknowledged the need for modernization.

However, the full Category 2 operation has been hampered by technical issues. Airport officials reported the facility was downgraded to CAT I. This was due to the inability to keep the full runway lighting system operational. One source noted a Thai Airways aircraft damaged the lighting system in late October.

In a previous winter, more than 40 flights were disrupted at the airport over an 18-day period. This illustrates the scale of the problem. Nearby Netaji Subhas Chandra Bose International Airport in Kolkata, India, already operates with a CAT II system.

Financial and Passenger Consequences

These diversions carry a substantial cost for airlines and passengers. Airlines face increased airline operational costs from several factors:

Additional fuel burn for flying to the alternate airport and returning.
Extra landing and parking fees at the diversion airport.
Schedule disruptions across the entire network.

The International Air Transport Association (IATA) stresses the importance of reliable airport infrastructure. Delays also cause severe inconvenience for passengers, especially transit passengers. A senior pilot from Biman Bangladesh Airlines confirmed the financial burden of diversions. Major aircraft manufacturers, such as Boeing, design their aircraft to utilize advanced ILS systems. The lack of an upgraded system at a major hub like HSIA creates a bottleneck for international air traffic. For more analysis on regional air travel challenges, visit our latest commercial aviation news at flying.flights.