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Delhi Airport Fog Delays, New Winter Upgrades

Travelers watch a departures board at Indira Gandhi International during Delhi airport fog delays as dense winter fog obscures the runways outside
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8 min read

Key points

  • Delhi airport fog delays may ease as Indira Gandhi International upgrades three CAT III capable runways and AI decision tools
  • A new Airport Predictive Operations Centre pools weather, air traffic and ground data to keep around 30 movements per hour in dense fog
  • Regulator defined fog season from December 10 to February 10, with airlines also deploying CAT III trained crews and aircraft
  • Past winters saw hundreds of Delhi flights delayed in a single day and hundreds of thousands of passengers affected by fog disruption
  • Travelers should avoid tight morning connections at Delhi in December and January and favor mid day or afternoon banks when possible
  • Alternatives such as Mumbai or Doha routes are worth considering for critical trips during the peak fog window

Impact

Where Impacts Are Most Likely
Expect the highest risk of disruptions on early morning arrivals and departures at Delhi during the December 10 to February 10 fog window
Best Times To Fly
Mid day and early afternoon flights are generally less exposed to dense fog, while late night and early morning waves carry more risk
Connections And Misconnect Risk
Travelers should allow at least three hours for domestic to international connections at Delhi in winter and avoid separate tickets on morning banks
Onward Travel And Changes
Have flexible rail or car plans from Delhi, monitor airline alerts closely, and be ready to accept rebooking to later same day flights or alternate hubs
What Travelers Should Do Now
For high stakes trips in December and January, book more robust connection windows at Delhi, consider Mumbai or Gulf hubs, and favor CAT III capable carriers

Delhi airport fog delays may ease for many long haul passengers this season, as Indira Gandhi International Airport (DEL) in Delhi, India, rolls out new CAT III runway upgrades and artificial intelligence tools ahead of the December 10 to February 10, 2025 to 2026 fog window. The changes target the dense morning fog that often brings long holding patterns, diversions, and mass cancellations across north Indian aviation in December and January. For travelers who depend on tight connections through Delhi between Europe, North America, and South Asia, the new setup could reduce risk, although winter itineraries will still need extra buffer and backup plans.

The core change is that Delhi airport fog delays are now being tackled with both additional CAT III capable runway ends and an AI assisted Airport Predictive Operations Centre that should keep more departures and arrivals moving during low visibility spells, while still accepting that severe fog can halt operations altogether.

Authorities at Delhi International Airport Limited, or DIAL, have confirmed that the Dwarka end of Runway 10/28 has been upgraded with a CAT III Instrument Landing System, completing a multi season plan to bring three runways, 10/28, 11L/29R, and 11R/29L, to CAT III standards at both ends. That means even when runway visual range falls well below traditional thresholds, the airport can keep accepting landings on more configurations instead of relying on a single low visibility runway, a bottleneck that previously created long airborne stacks and diversions.

In parallel, DIAL has introduced a new high tech Airport Predictive Operations Centre, often described as APOC, where airside operations, air traffic control representatives, airline duty managers, and ground handlers can see the same live picture of weather, runway capacity, and gate usage. The APOC uses AI driven decision support and predictive analytics to recommend which runway to prioritize, how to sequence arrivals and departures, and when to pre emptively retime or cancel flights, with the stated goal of sustaining around 30 movements per hour even in dense fog and cutting recovery time after a fog spell by nearly four hours.

The new systems draw on improved fog forecasting as well. Delhi airport has integrated data from India s Winter Fog Experiment, known as WiFEX, which has reached about 85 percent accuracy in predicting fog events at Indira Gandhi International and other northern airports, giving operations teams more time to slim schedules, swap aircraft, or adjust crew plans before visibility collapses. On the airline side, carriers such as Air India have activated winter fog playbooks that include rostering extra cockpit crews trained in low visibility operations and positioning more CAT III B equipped aircraft at fog prone bases.

Background

Delhi and other cities in the northern Indo Gangetic plain sit under a recurring winter inversion, where cold air, moisture, and pollution combine to create thick radiation fog that can persist for hours around dawn. When runway visual range drops below a few hundred meters, only CAT III equipped runways, aircraft, and crews can land and depart, which sharply reduces capacity and, in the worst cases, temporarily stops operations. The Directorate General of Civil Aviation, or DGCA, now defines an official fog window from December 10 to February 10 each winter, a period when airlines and airports are expected to run specific low visibility plans.

How it Works

CAT III Instrument Landing Systems use highly precise radio signals, on board receivers, and autopilot modes that can guide an aircraft to the runway even when pilots cannot see the lights until the last moments of landing. Delhi already had some CAT III capability, but with three runways now certified at both ends, controllers have more flexibility to juggle wind shifts, runway maintenance, and traffic flows without forcing long single file queues on one side of the airfield. The APOC overlays that with algorithms that simulate traffic for the next few hours based on forecast visibility, inbound loads, and gate turns, then suggests when to proactively thin schedules or swap aircraft to minimize knock on disruption.

The long term stakes are clear from recent winters. In January 2024, one of the foggiest months in recent years, DGCA data show that about 480,000 passengers were affected by delays or cancellations across India, roughly double the previous year, with Delhi and Mumbai among the worst hit airports. On individual peak days at Delhi, local reporting recorded more than 400 flights delayed and dozens canceled or diverted as visibility stayed near zero for hours, leaving thousands of passengers stranded in terminals. That kind of disruption can ripple across long haul networks for days.

For Adept s readers, this new Delhi upgrade follows earlier investment stories that still matter for planning. Prior to the current fog season, Delhi closed Runway 10/28 for 90 days from June 15 to September 15, 2025, canceling around 114 flights per day and rescheduling about 86 to upgrade the runway surface and low visibility systems specifically to improve winter resilience. Taken together with the APOC rollout, DIAL is signaling that it sees fog management as a structural priority, not just an annual scramble.

From a traveler s point of view, the most important takeaway is that the risk profile is shifting, not disappearing. Early morning departures and arrivals in the 400 a.m. to 1000 a.m. band remain the most exposed to zero visibility spells in December and January. The new systems should reduce the length of recovery once fog lifts and allow more of those flights to land or depart, but they do not stop the fog itself. Mid day and early afternoon flights, when radiation fog usually burns off, are still the safer choice for critical trips, especially for those connecting between long haul flights or between long haul and domestic sectors.

Connections also need fresh thinking. In past winters, travelers on two to three hour domestic connections at Delhi often found themselves stuck when a morning delay pushed their feeder flight past boarding for an onward long haul. With improved CAT III capacity, the odds of complete shutdown are lower, but ATC may still meter departures to keep runway use within safe limits. A conservative rule of thumb for this winter is to plan at least three hours for domestic to international connections at Delhi, and four hours when flying on separate tickets or when checked baggage must be reclaimed and rechecked.

It is also time to weigh alternatives more consciously. For itineraries where Delhi is only a transfer point, routing via Chhatrapati Shivaji Maharaj International Airport (BOM) in Mumbai or via hubs such as Hamad International Airport (DOH) in Doha can reduce exposure to north India fog, even if the total flight time is slightly longer. This may be especially worthwhile for short business trips, medical travel, or trips with non flexible appointments at the destination. That said, for many travelers starting or ending in Delhi, the upgraded systems at Indira Gandhi International will remain the most practical option, but they should be paired with more robust connection buffers, flexible hotel bookings, and travel insurance that covers weather disruption.

Travelers who want a deeper sense of how winter fog interacts with Indian aviation can review Adept s explainer on how winter fog disrupts flights in India, which breaks down runway visual range categories, diversion patterns, and airline waiver practices. Those planning trips that cross both Indian winter weather and other global systems may also find value in earlier coverage of how large weather events, such as atmospheric rivers and blizzards, snarl complex itineraries, since the planning logic is similar even when the weather driver is different.

In practical terms, the best strategy for this winter is to treat Delhi as a better equipped but still weather sensitive hub. Book mid day or early afternoon departures when possible, avoid very tight morning connections in December and January, confirm that chosen airlines operate CAT III equipped aircraft with trained crews on critical legs, and keep an eye on DGCA and airline advisories in the week before travel. The new AI and CAT III investments should shorten the worst disruptions and speed recovery, but resilience will come from a combination of smarter infrastructure and more conservative itineraries.

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