Dense fog and severe pollution choke Delhi, flights and trains disrupted

Delhi remained shrouded in dense fog on Monday morning, with visibility dropping to near zero across large parts of the city, severely affecting road traffic and transport services.

The India Meteorological Department (IMD) issued an orange alert for fog and urged people to exercise caution. According to the IMD, the minimum temperature dipped to 8.2 degrees Celsius overnight.

The foggy conditions coincided with a sharp deterioration in air quality. Delhi’s Air Quality Index (AQI) plunged into the “Severe Plus” category, crossing 456. In Ashok Vihar, the AQI touched the maximum level of 500 during the early hours of the day.

Several areas reported alarmingly high pollution levels. Visuals from Anand Vihar and Akshardham showed thick toxic smog engulfing the neighbourhoods, with AQI readings at 493, placing them in the ‘Severe’ category. Dwarka also witnessed similar conditions, recording an AQI of 469, which falls under the ‘Severe’ bracket. In neighbouring Noida, air quality deteriorated further, with the AQI reaching 454, categorised as ‘Severe Plus’.

As per official classification, an AQI of 51–100 is considered ‘satisfactory’, 101–200 ‘moderate’, 201–300 ‘poor’, 301–400 ‘very poor’, 401–450 ‘severe’, and 451–500 ‘severe plus’.

Videos circulating on social media showed dense fog blanketing much of the Delhi-NCR region, reducing visibility to near zero and making driving conditions extremely hazardous.

In response to the worsening weather, Delhi airport issued an advisory on Monday morning warning passengers of possible delays in flight operations. Travellers were advised to check with their respective airlines before heading to the airport.

“Due to dense fog, flight operations may experience disruptions. We are working closely with all stakeholders to minimize inconvenience to passengers. For the latest flight updates, passengers are advised to contact their respective airlines. We sincerely regret any inconvenience caused,” the advisory stated.

IndiGo also released a separate advisory, asking passengers to stay updated on their flight status through its website or mobile application.

“Low visibility and fog over Delhi will impact flight schedules. We're keeping a close watch on the weather and doing our best to get you where you need to be, safely and smoothly. We request you to stay updated on your flight status via our website or app. Be assured, our teams are here to assist you at every step and ensure support. Here's hoping dearer skies help us serve you better soon and thank you for your patience and understanding during this challenging time,” the airline said.

<blockquote class="twitter-tweet"><p lang="en" dir="ltr">Low visibility and fog over <a href="https://twitter.com/hashtag/Delhi?src=hash&amp;ref_src=twsrc%5Etfw">#Delhi</a> will impact flight schedules. We&#39;re keeping a close watch on the weather and doing our best to get you where you need to be, safely and smoothly.<br><br>We request you to stay updated on your flight status via our website or app. Be assured, our teams…</p>&mdash; IndiGo (@IndiGo6E) <a href="https://twitter.com/IndiGo6E/status/2000392531130118265?ref_src=twsrc%5Etfw">December 15, 2025</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>

Rail services in North India were similarly affected, with Indian Railways reporting delays to around 60 trains, some running several hours late due to the dense fog.

Meanwhile, health experts warned of serious risks associated with prolonged exposure to toxic air. Speaking to news agency PTI, an expert advised people to avoid outdoor walks or exercise, particularly in the morning hours. She suggested stepping out only when absolutely necessary, preferably later in the day when sunlight helps disperse pollutants, and stressed that wearing masks is essential for those who must venture out for work.