As Delhi’s AQI hits ‘severe’, experts warn of rising vitamin D deficiency; recommend supplements for all

Delhi’s smog isn’t just choking the lungs — it’s blocking the sun. Here’s why your bones, mood and immunity need extra vitamin D this winter.

As the air quality in the Delhi‑NCR region plummets into “severe” and “severe +” categories, a less-visible health risk is coming into focus: the lack of vitamin D. Sky-darkened by smog and particulate matter, the sunlight we rely on for our “sunshine vitamin” simply can’t reach our skin. Experts now warn that even without stepping into a doctor’s office, city-dwellers may need to consider supplementation.

Why Does the Smog Matter for Vitamin D?

The skin makes vitamin D when it gets UVB rays from the sun.

But smog and pollution in the air block these UVB rays. In Delhi, where daily AQI scores went above 400—more than 30 times the safe limit set by the World Health Organization—people have much less chance to make vitamin D.

City life makes this worse because of lots of time indoors, sunscreen use, clothes that cover up, and tall buildings all cut down on direct sun on the skin. Hormone doctors know there's a gap between sun time and how much vitamin D we make. They say it's best to take steps to prevent low levels.

Also Read: Vitamin D benefits for bones, immunity, and muscles and who is most at risk of low levels

How Much Supplements Are Recommended?

Recognising the gap between sun exposure and actual vitamin D production, endocrine experts recommend a preventive approach.

In dirty-sky zones like Delhi-NCR:

Adults: ~2,000 IU of vitamin D daily.

Adolescents: ~1,000 IU daily.

Children: 600–1,000 IU daily.

Doctors caution against mega-doses or unsupervised supplementation—too much vitamin D can lead to hypercalcaemia, kidney stones or other complications.

Why Your Bones and More May Be at Risk

Vitamin D does more than keeping your bones strong. A 2024–25 meta-analysis found that about one in five Indians suffers from dangerously low vitamin D levels.

In polluted cities, this deficiency adds up to weak bones, higher fracture risk, reduced immunity, fatigue, and even mood disturbances.

What You Can Do—Even When the Sky Is Grey

1. Get safe sunlight when possible: Even in pollution, a short daily exposure—arms and legs uncovered—helps.

2. Look at what you eat: Try foods high in vitamin D: fatty fish, egg yolks, milk or cereals with added vitamin D.

3. Consider supplements: Especially if you live in a high-pollution city and find limited sun exposure. But do it under medical guidance.

4. Indoor air matters: Though we breathe thousands of litres daily, polluted air reduces the skin’s ability to produce vitamin D. Clean indoor air and air filter use may help.

5. Regular check-ups: If your bones hurt, your muscles feel weak, or you're tired a lot—talk to your doctor about checking your vitamin D and how much you might need to take.

Also Read: Hyderabad-based doctor warns not to make these 3 mistakes while taking Vitamin D supplement

In a city where the sky is grey more often than not, vitamin D deficiency isn’t just a seasonal matter—it’s a chronic risk. As smog continues to block the sun’s cues, being proactive about your vitamin D status becomes a health priority. Combine smart supplementation with safe daily habits, and you’ll counter one of the hidden harms of polluted air.

FAQs on air pollution and vitamin D deficiency

1. How does air pollution affect vitamin D levels?

Air pollution blocks UVB rays from reaching the skin, reducing the body’s ability to produce vitamin D naturally.

2. Why is vitamin D important for health?

Vitamin D supports bone strength, immune function, and mood regulation. Deficiency can lead to weak bones, fatigue, and frequent illness.

3. How much vitamin D do adults need daily?

Experts recommend about 2,000 IU per day for adults in high-pollution areas like Delhi, preferably under medical supervision.

4. Can food help improve vitamin D levels?

Yes. Include fortified milk, egg yolks, fatty fish like salmon, and mushrooms in your diet to boost vitamin D intake.

5. Is it safe to take vitamin D supplements?

Supplements are safe when taken in prescribed doses. Overuse can lead to excessive calcium levels or kidney issues.