In Delhi, Winter Arrives With AQI Alerts.In Delhi, Winter Arrives With AQI Alerts.

June 17, 2026

In Delhi, Winter Arrives With AQI Alerts.

In Delhi, winter does not arrive quietly. It arrives with AQI alerts.

I remember landing in Delhi in November 2025 and looking out of the aircraft window, waiting for the runway to appear. It did not. For a few seconds, I genuinely thought we were still mid-air because everything outside was white. Not cloudy white. Delhi white. Pale yellow, thick smog everywhere. The kind that makes a pilot’s landing feel like an act of faith.

The numbers explain the mood.

In 2025, Delhi met India’s daily PM2.5 standard on only 156 out of 365 days. In winter, it met that standard on just four days. The WHO’s stricter daily PM2.5 guideline was met on only five days across the entire year (Agarwal). That is not just bad air. That is a calendar problem.

Winter makes pollution harder to escape because the atmosphere behaves differently. Lower temperatures, calmer winds, lower mixing heights and inversion conditions can trap pollutants closer to the ground (“Air Pollution Caused by Stubble Burning”; “Weather Patterns and Pollution”). Think of it as the city putting a lid on itself.

This is why winter air feels heavier. It is not only colder. It is carrying more of the city. 

 

But Delhi is not the whole story. It is simply the loudest one.

In 2025, Mumbai saw areas move into the “very poor” AQI range in November (“Very Poor Air in 2 Areas”). Bengaluru’s Silk Board area recorded AQI levels close to “poor” in May, with PM10 levels well above WHO’s 24-hour guideline (“Despite Flyover Construction Ending”). Hyderabad saw multiple locations cross AQI 250 in December (Shah). Chennai, despite the sea breeze myth, recorded AQI levels largely between 150 and 200 during December pollution episodes (Tripathi).

Every major Indian city has its own version of the same problem. Outdoor pollution becomes an indoor routine. It enters homes, offices, classrooms, gyms and cafés through doors, windows, balconies, ducts and the usual gaps every building has. Once inside, it mixes with cooking fumes, incense, cleaning sprays, dust, humidity, closed air-conditioning and whatever the room is already holding. The EPA notes that poor ventilation can increase indoor pollutant levels by failing to dilute or remove them (“Introduction to Indoor Air Quality”).

The fix does not need to be theatrical.

Check the AQI. Ventilate when outside air is better. Reduce indoor smoke and strong sprays. Control dust. Manage humidity. Use proper filtration in rooms where people spend long hours. Lastly, wear masks, people!

Delhi makes the air problem obvious.

The rest of India makes it normal.

And that is the point: better air is no longer a Delhi conversation. It belongs in every city, and in every room we use daily.

Works Cited

Shah, Khyati. “Ab Dilli Dur Nahi: Hyderabad’s Air Slips into ‘Severe’ Zone.” The New Indian Express, 20 Dec. 2025. https://www.newindianexpress.com/states/telangana/2025/Dec/20/ab-dilli-dur-nahi-hyderabads-air-slips-into-severe-zone

Agarwal, Priyangi. “In 2025, Delhi Met National PM2.5 Standards on Just 156 Days — Mere 4 of These in Winter.” The Times of India, 20 Jan. 2026 https://timesofindia.indiatimes.com/city/delhi/in-2025-delhi-met-national-pm2-5-standards-on-just-156-days-mere-4-of-these-in-winter/articleshow/126707620.cms

“Air Pollution Caused by Stubble Burning.” Press Information Bureau, Government of India, Ministry of Environment, Forest and Climate Change, 25 Nov. 2024 https://www.pib.gov.in/PressReleaseIframePage.aspx?PRID=2076918&reg=3&lang=2

Anush S. “Despite Flyover Construction Ending, Silk Board in Bengaluru Struggles with Air Pollution.” The Times of India, 14 July 2025 https://timesofindia.indiatimes.com/city/bengaluru/despite-flyover-construction-ending-silk-board-in-bengaluru-struggles-with-air-pollution/articleshow/122422228.cms

“Introduction to Indoor Air Quality.” United States Environmental Protection Agency, 19 Mar. 2026 https://www.epa.gov/indoor-air-quality-iaq/introduction-indoor-air-quality

Patel, Mahiyar. “‘Very Poor’ Air in 2 Areas as Mumbai’s AQI Worsens to 198; Visibility Severely Hit.” The Times of India, 26 Nov. 2025 https://timesofindia.indiatimes.com/city/mumbai/very-poor-air-in-2-areas-as-mumbais-aqi-worsens-to-198-visibility-severely-hit/articleshow/125592999.cms

“Weather Patterns and Pollution.” Press Information Bureau, Government of India, Ministry of Earth Sciences, 3 Aug. 2022 https://www.pib.gov.in/PressReleasePage.aspx?PRID=1847740&reg=48&lang=2

Tripathi, Shweta. “Why Has Chennai’s AQI Breached 160 despite the Beach?” The Federal, 17 Dec. 2025 https://thefederal.com/category/states/south/tamil-nadu/why-has-chennais-aqi-breached-160-despite-the-beach-221187

Keep Reading

More blogs for you

Contact usView all blogs
JB for Hospitality
June 30, 2026

JB for Hospitality

In 2025, India’s average PM2.5 level was nearly 10x the WHO annual guideline of 5 µg/m³ (IQAir). That is the outdoor air entering your hotel, cafe or restaurant, before it mixes with guest rooms, lobbies, busy kitchens and service hours mixed with forced air freshener. For hotels, good air should feel like part of the stay, not another operational headache. JB helps properties roll out cleaner guest rooms and shared spaces quietly, with AMC support and flexible filter plans.

Read blog
JB for Gyms
June 30, 2026

JB for Gyms

In 2025, India’s average PM2.5 level was nearly 10x the WHO annual guideline of 5 µg/m³ (IQAir). That is the outdoor air entering your gym, where it mixes with heavy breathing, sweat, rubber flooring and long training hours. Gyms work hard all day. So does the air inside them. JB helps fitness spaces stay fresher with room-wise rollout, AMC support and filter plans that are easy to manage.

Read blog
JB for Healthcare
June 30, 2026

JB for Healthcare

In 2025, India’s average PM2.5 level was nearly 10x the WHO annual guideline of 5 µg/m³ (IQAir). That is the outdoor air entering your hospital or clinic every day, before it mixes with waiting rooms, corridors and consultation spaces. In a hospital/clinic, air is part of the care experience. JB helps teams keep it cleaner, quietly, with room-wise rollout, AMC support, remote visibility and filter plans that do not become another admin headache.

Read blog
The Missing Filter in the Modern Home.
June 17, 2026

The Missing Filter in the Modern Home.

We are very good at inspecting what goes into the body. We read labels. We filter water. We compare oils, avoid certain ingredients, ask where our food comes from, and choose skincare with more seriousness than some people choose apartments. Fair enough. The modern Indian home already understands filtration. RO water is normal. Better cooking oil is normal. Fresh produce is normal. The one thing still getting a free pass is air. Which is odd, because air is not occasional. The average human breathes around 25,000 times a day and inhales about 11,000 litres of air, according to Lung Care Foundation. The U.S. Environmental Protection Agency also notes that people spend about 90% of their time indoors (EPA, 2026).

Read blog
Why Gyms Need Better Air
June 17, 2026

Why Gyms Need Better Air

The harder you train, the more air your body demands. Every workout asks the body to move more air. During exercise, breathing becomes faster and deeper. One review in Breathe notes that ventilation can rise from around 12 litres of air per minute at rest to as much as 100 litres per minute during intense exercise (“Your Lungs and Exercise”). That is the part people forget. In a gym, you are not just sharing equipment. You are sharing room air. Most gyms understand surface hygiene. Wipe the bench. Clean the mat. Sanitise the handles. Keep the changing rooms decent. All of that matters. But it is only the obvious part of the problem. The less obvious part is what the room is holding.

Read blog
Is Indoor Air the Same as Outdoor Air?
June 17, 2026

Is Indoor Air the Same as Outdoor Air?

No. Indoor air is not the same as outdoor air. It begins as outdoor air, but once it enters a room, the room changes it. Air enters buildings through windows, doors, balconies, corridors, ventilation systems, ducts, gaps and the small leaks every building has. The U.S. Environmental Protection Agency describes this through three routes: infiltration, natural ventilation and mechanical ventilation (“Introduction to Indoor Air Quality”). So yes, the outside gets in. But it does not stay the same.

Read blog
We Breathe Between 9,000 To 11,000 Litres Of Air A Day.
June 16, 2026

We Breathe Between 9,000 To 11,000 Litres Of Air A Day.

The average human breathes somewhere between 9,000 and 11,000 litres of air every day. Lung Care Foundation places the number at around 11,000 litres a day, across nearly 25,000 breaths (“Lung Basics”). That is a lot of air to leave unexamined. We think about the water we drink. We think about the food we eat. We check ingredients, compare oils, buy better skincare, track sleep, book Pilates, and try to reduce stress.

Read blog
In Delhi, Winter Arrives With AQI Alerts.