On the eve of a new year, Delhi isn’t just ringing in 2026—it’s gasping for breath. A suffocating blanket of Delhi fog, laced with toxic pollutants, has once again paralyzed the national capital. The result? Mass flight cancellations, delayed trains, and an Air Quality Index (AQI) that’s plunged into the ‘Very Poor’ to ‘Severe’ category, leaving millions in a state of anxiety and disruption .
Table of Contents
- Delhi Fog: The Great Travel Disruptor
- Behind the Scenes: How the CAT III Protocol is a Lifeline
- More Than Just Fog: Delhi’s Toxic Air Crisis
- What This Means For You: A Practical Guide
- Is This the New Winter Normal for Delhi?
- Conclusion
- Sources
Delhi Fog: The Great Travel Disruptor
The Indira Gandhi International (IGI) Airport, one of the busiest in South Asia, has become a scene of chaos. On December 31, 2025, dense fog has led to a significant number of flight operations being axed. Reports indicate that over 100 flights—both arrivals and departures—have been cancelled, with many others suffering severe delays or diversions to other cities .
Airlines like IndiGo have proactively issued travel advisories, urging passengers to check their flight status before heading to the airport. The disruption isn’t limited to the skies; it’s spilled onto the rails and roads. Train services across Northern India are experiencing hours-long delays, and the near-zero visibility on highways has brought a large part of the city’s road traffic to a crawl, creating a logistical nightmare for commuters .
Behind the Scenes: How the CAT III Protocol is a Lifeline
Despite the grim outlook, all is not lost at IGI Airport. The facility is equipped to handle such extreme weather thanks to its CAT III protocol capabilities. But what exactly is this technical term?
In simple terms, a CAT III (Category III) Instrument Landing System (ILS) is the most advanced of its kind. It allows specially trained pilots in certified aircraft to land safely in conditions of extremely low visibility—sometimes with no visual contact with the runway at all . The decision height for a CAT IIIB landing can be as low as 50 feet, or even none, with a runway visual range (RVR) of just 75 meters .
While this technology is a critical safety net, it’s not a magic fix. It requires specific aircraft, pilot certification, and coordination with Air Traffic Control. This means that while some essential flights can still operate, the overall capacity of the airport is drastically reduced, leading to the inevitable backlog of cancellations and delays we’re seeing now.
More Than Just Fog: Delhi’s Toxic Air Crisis
What many perceive as a natural winter inconvenience is, in reality, a potent cocktail of weather and human-made pollution. The fog isn’t just water vapor; it’s smog—a toxic mix of fog and smoke. On December 31, 2025, Delhi’s AQI has been hovering in the ‘Very Poor’ category, with forecasts warning it could deteriorate to ‘Severe’ levels by New Year’s Day , .
Real-time data from monitoring stations has shown AQI figures spiking to alarming levels, with some areas reporting indices well above 600, which is classified as ‘Hazardous’ for all individuals , . This isn’t just an environmental issue; it’s a major public health emergency. Residents, especially children, the elderly, and those with respiratory conditions, are at significant risk. The recommendation is clear: avoid any outdoor exertion and stay indoors with air purifiers running if possible [[INTERNAL_LINK:delhi-air-pollution-health-tips]].
What This Means For You: A Practical Guide
If you’re in Delhi or planning to travel through it, here’s what you need to do:
- For Air Travelers: Do not go to the airport without confirming your flight status directly with your airline. Expect delays and be prepared for last-minute cancellations.
- For Rail Passengers: Check the running status of your train on the IRCTC or NTES app. Delays of several hours are common during such dense fog spells.
- For Residents: Stay indoors, especially during the morning and evening hours when pollution is at its peak. Use an N95 mask if you must go outside. Keep windows and doors shut.
- Monitor the AQI: Use trusted apps or websites like aqicn.org or the Central Pollution Control Board’s portal to track real-time air quality in your specific locality.
Is This the New Winter Normal for Delhi?
This annual cycle of fog, flight chaos, and hazardous air raises a critical question: has this become an accepted, albeit miserable, part of Delhi’s winter identity? While the meteorological conditions of low wind speed and low temperatures create a perfect trap for pollutants, the primary sources—vehicular emissions, industrial activity, construction dust, and the ever-controversial stubble burning in neighboring states—remain largely unaddressed at a systemic level [[INTERNAL_LINK:delhi-pollution-causes-solutions]].
The reliance on advanced technology like CAT III protocols is a testament to our ability to adapt, but it doesn’t solve the root cause. It’s a band-aid on a much deeper wound. For the residents of Delhi, the hope for a clear, healthy winter sky seems to be a distant dream, pushed further away with each passing year of inaction.
Conclusion
The dense Delhi fog of December 2025 is more than a weather event; it’s a stark reminder of the city’s environmental and infrastructural challenges. While aviation technology like the CAT III protocol provides a crucial safety buffer for air travel, the underlying issue of toxic air quality demands urgent, sustained, and multi-faceted action from all stakeholders. Until then, the capital’s residents will continue to ring in the new year not with hope, but with a mask over their face and a weather app on their phone.