Delhi, India Air Quality & Smog

Dominant pollutants, when pollution and smog are worst, a notable historical episode, and the official monitoring agencies for Delhi, India — plus how to check the current reading. Delhi reports air quality on the National Air Quality Index — our full guide explains how that scale works and how it compares to the US AQI.

Dominant pollutants

PM2.5, PM10 — among the highest urban particulate levels of any major city on Earth.

Seasonal pattern: when smog is worst

Delhi's air collapses every autumn and winter. From roughly October to January, crop-residue ("stubble") burning across Punjab and Haryana combines with Diwali fireworks, winter temperature inversions, and year-round vehicle and industrial emissions. The National AQI routinely reads "Severe" (above 400) and on the worst days runs off the 0–500 scale entirely.

A notable air-quality episode

After Diwali in November 2016, Delhi suffered the "Great Smog" — visibility collapsed and schools closed for days. Severe episodes recurred in November 2017 and 2019, triggering the Graded Response Action Plan, school closures, construction bans, and the odd-even vehicle-rationing scheme.

The local index and who runs it

Delhi reports air quality using the National Air Quality Index, not the US AQI — so the same air can read as a different number than you may be used to. The CPCB national portal and SAFAR publish station-level AQI and forecasts for Delhi-NCR, including the share attributable to stubble-burning smoke.

• Central Pollution Control Board (CPCB)
• Delhi Pollution Control Committee (DPCC)
• SAFAR (Ministry of Earth Sciences)

How to check air quality in Delhi

For the official live reading, the agency portals above are the canonical source. To understand what the numbers mean, start with our guide to the National Air Quality Index and the broader comparison of world air-quality indices. Smog Report puts glanceable air quality on your iPhone — widgets, Live Activities, Siri, and Apple Watch — free and with no account.

Common questions about Delhi air quality

Why does Delhi have air-quality and smog problems?

Delhi's air collapses every autumn and winter. From roughly October to January, crop-residue ("stubble") burning across Punjab and Haryana combines with Diwali fireworks, winter temperature inversions, and year-round vehicle and industrial emissions. The National AQI routinely reads "Severe" (above 400) and on the worst days runs off the 0–500 scale entirely.

What are the main air pollutants in Delhi?

Delhi's dominant pollutants are PM2.5, PM10 — among the highest urban particulate levels of any major city on Earth. The reading on any given day is usually driven by whichever of these is highest.

Has Delhi had a major air-quality or smog event?

After Diwali in November 2016, Delhi suffered the "Great Smog" — visibility collapsed and schools closed for days. Severe episodes recurred in November 2017 and 2019, triggering the Graded Response Action Plan, school closures, construction bans, and the odd-even vehicle-rationing scheme.

What air-quality index does Delhi use?

Delhi reports air quality on the National Air Quality Index (AQI), not the US AQI — so the same air can read as a different number than you may be used to. For live, glanceable readings on your iPhone, the free Smog Report app auto-selects the right local index for wherever you are.

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