MC EXPLAINER Decoding the ongoing traffic chaos at Delhi airport

The civil aviation minister called an urgent meeting on April 20 with the executives of operator DIAL, the Airports Authority of India (AAI) and domestic airlines to discuss issues leading to the flight disruptions. The minister directed DIAL to reopen IGI airport's main runway 10/28 by the first week of May amid concerns over flight delays due to a runway closure for up gradation.

In recent weeks, Delhi’s Indira Gandhi International Airport—India’s busiest—has found itself at the centre of a logistical storm. Since early April, passengers, pilots, air traffic controllers and airline staff have faced mounting delays, cancellations and diversions. The disruption has drawn criticism from both the travelling public and prominent politicians.

On April 21, Omar Abdullah, the Chief Minister of Jammu and Kashmir, publicly complained after his flight from Jammu to Delhi was delayed. Nine days later, Congress MP Shashi Tharoor went further, calling the airport “dysfunctional”.

The situation, as data from Flightradar24 suggests, is more than just a temporary inconvenience. On May 2, average departure delays at Delhi airport stood at 50 minutes, with arrivals lagging by 35 minutes.

The following day, 155 flights were delayed and six cancelled. Earlier, on April 20th, over 68 percent of the 1,300 scheduled flights were disrupted. For passengers, the airport has become a source of frustration. For airlines and the operator—Delhi International Airport Ltd (DIAL), a GMR Airports entity—the challenge is to prevent the situation from worsening.

A perfect storm of planning, infrastructure and wind

At the heart of the crisis is the temporary closure of Runway 10/28, announced by DIAL on April 8 to upgrade the instrument landing system (ILS). This runway, the second oldest at the airport and close to Terminals 1 and 2, is critical for managing Delhi’s domestic air traffic. Though the closure was approved in advance by the Airports Authority of India (AAI), its timing coincided with the onset of unseasonal easterly winds and early summer thunderstorms—an unfortunate mix that restricted available runway combinations for takeoffs and landings.

Delhi has four operational runways, but only two of them—10/28 and 11R/29L—support Category III-B landings, which are necessary during low visibility. At present, Runway 10/28 supports such operations from only one end. The ongoing ILS upgrade will allow low-visibility operations from both directions, which is crucial for Delhi’s fog-prone winter season.

The airport’s operators had, in fact, requested permission to close Runway 10/28 as early as April 1, 2025, to ensure that the upgrade would be complete before winter. The AAI granted this, albeit with caveats: during easterly winds, only 32 arrivals would be permitted, and 42 during westerlies. A formal NOTAM (Notice to Airmen) issued on April 11 restricted arrivals accordingly until July 21.

What went wrong?

Though DIAL argues that the timing and constraints were well-communicated to airlines months in advance, the disruption has revealed deeper coordination failures.

According to DIAL executives present at an April 21 meeting convened by Civil Aviation Minister, Kinjarapu Rammohan Naidu, domestic carriers made minimal changes to their schedules despite advance warnings. On April 20 alone, nearly 900 flights—68 percent of total traffic—were delayed. The operator claims much of the chaos could have been avoided if airlines had restructured their schedules in line with projected wind patterns.

DIAL has proposed that airlines cancel 19 morning flights and reschedule 75 others to night slots to reduce peak-time pressure. Airlines, however, estimate that such adjustments would result in losses exceeding Rs 1,000 crore, given the high demand for morning departures and the commercial sensitivity of existing routes.

Network planning appears to have failed at multiple levels. The existing slot allocation system did not adjust for the reduced capacity during runway shutdown and easterly wind conditions. The lack of a dynamic response—either by the AAI, air traffic control, or the airlines—exacerbated the issue. During peak congestion, aircraft were forced to circle in the air or divert to nearby airports.

Why do winds matter?

Runway orientation is designed to allow aircraft to take off and land in the wind — a requirement that ensures lift during takeoff and stability during landing. In Delhi, wind direction influences the runway combinations that can be used. When easterlies blow, takeoffs are limited to runways 09 and 11L, while landings are permitted only on 11R. Westerly winds offer greater flexibility: runway 27 allows mixed-mode operations (both takeoffs and landings), while 29L and 29R handle landings and departures separately.

April and May typically mark the transition to easterlies. This year, they arrived earlier and more forcefully than expected, compounding the effect of one runway being out of service. Thunderstorms further curtailed operations. On April 20, DIAL reported significant weather disruptions during peak hours, just as airline timetables remained rigid.

When will the situation improve?

DIAL says that congestion will ease by May 8 when Runway 10/28 reopens temporarily.

Following the April 21 meeting, the Centre permitted DIAL to reschedule the ILS upgrade for a full shutdown starting June 15, lasting for three months. The hope is that this will offer a longer maintenance window during relatively stable weather conditions.

Yet , deeper concern remains. As India’s aviation sector grows and Delhi’s air traffic surges, the capital’s airport is dangerously close to capacity limits. Infrastructure upgrades, while necessary, must be accompanied by responsive scheduling, better forecasting, and clear communication between stakeholders. Without that, what is unfolding now may not be a one-off crisis, but a recurring feature.