Delhi’s winter woes have deepened as a lethal mix of dense fog and extreme air pollution continues to choke the national capital. With the Air Quality Index (AQI) hovering close to 400 — firmly in the “severe” category — residents across Delhi-NCR are breathing toxic air, even as visibility remains dangerously low due to persistent fog.
While fog has disrupted daily routines and transportation, experts warn that the more serious threat lies in the pollution trapped beneath it. The combination has turned large parts of the city into a health hazard zone, affecting millions.
Flight Operations Hit As Visibility Plummets
According to the India Meteorological Department, visibility at the Indira Gandhi International Airport dropped sharply, touching just 1.1 km at 10:00 UTC, with runway visual range reduced to nearly 2 km, as reported by NDTV. These conditions led to widespread disruption in air travel. A total of 78 incoming flights and 70 departures were cancelled, while two flights were diverted.
The situation followed heavy cancellations a day earlier, when 118 flights were scrapped. Despite the use of CAT-III landing systems — designed to allow aircraft to land in extremely low visibility — delays and cancellations have persisted, underscoring the severity of conditions.
December 2025 Among Delhi’s Worst In Ten Years
Delhi’s air quality data reveals a troubling long-term pattern. Over the past decade, December AQI levels have consistently fallen in the “very poor” to “severe” range. December 2025 now stands as the city’s third-worst December in ten years, with an average AQI of 349 — the worst since 2018.
Environmental experts explain that winter fog acts as a barrier, preventing pollutants from dispersing and causing them to accumulate closer to the ground. With calm winds and falling temperatures, pollution levels spike rapidly. As foggy conditions are expected to continue, air quality is likely to deteriorate further, increasing respiratory and cardiovascular risks.
On Monday, Delhi’s average AQI stood at 402. Of the monitoring stations across the city, 22 reported “severe” air quality, 14 were marked “very poor,” and only one recorded “poor” levels. Vivek Vihar in East Delhi emerged as the most polluted area, logging an AQI of 456.
Data shows that farm fires accounted for just 3.5 percent of PM2.5 pollution, indicating that local emissions combined with unfavourable weather conditions were the primary drivers. The most polluted day of 2025 was December 14, when AQI surged to 461, with several other days in November and December also breaching severe levels.