Explained: Why is Delhi’s AQI about 100 points worse than Gurugram’s?

New Delhi: Do you know why Delhi’s AQI has been sitting roughly 100 points above Gurugram for most of November, even though the public narrative still pins the blame on Punjab’s farm fires? 

Why has Delhi kept hovering near the “severe” edge, while Gurugram stays relatively cleaner, often closer to the “poor to very poor” band? And if both cities are in the same NCR bowl, why is the gap so stubborn. Is GRAP-III failing, or is the real pollution source no longer where we have been looking?

The daily CPCB bulletins from November 9 to 23 answer these questions more clearly than any press conference.

The pattern is simple. The UP border belt stays dirtiest. Delhi comes next, close behind. Gurugram stays much lower despite being right next to Delhi.

On November 24, that order repeated again. Ghaziabad was at 396 and Greater Noida at 382. Delhi was at 381. Gurugram was far lower at 286.

A day earlier on November 23, Ghaziabad was at 434 and Greater Noida at 421, both in the “severe” bracket. Delhi was at 378. Gurugram was far lower at 272.

On 22nd, the gap was even sharper. Ghaziabad 468, Greater Noida 416, Noida 394, Delhi 412, Gurugram 291.

On November 17, the same geography held. Ghaziabad 401, Greater Noida 390, Noida 390, Delhi 351, Gurugram 253.

On November 15, it was Ghaziabad 392, Greater Noida 418, Noida 370, Delhi 386, Gurugram 305.

Even on November 13, when Delhi touched 404, the UP cities were already crowding the top tier – Ghaziabad 370, Greater Noida 377, Noida 389 – while Gurugram stayed at 300.

So the idea that Gurugram should be as dirty as Delhi just because they share a border does not hold in the data. 

For two straight weeks, Delhi has tracked closer to the UP belt than to Gurugram. That is not a coincidence. It is a direction.

The split becomes clearer after November 11. Before that date, Delhi was slightly higher than the UP belt on a couple of days. But once the season moved into its fire peak, Ghaziabad, Noida and Greater Noida rose above or at par with Delhi almost daily, while Gurugram remained noticeably lower. 

November 12 captured that turning point early. Delhi was at 418, but Noida was already higher at 408, while Gurugram sat lower at 350.

What changed after November 11 was not Delhi’s local emissions alone. What changed was the external smoke load entering NCR.

This year, Punjab and Haryana have cut paddy-residue fires sharply. Their numbers are at a fraction of earlier seasons. 

The Union government’s ICAR satellite record up to November 23 shows Punjab at 5,088 fires and Haryana at 617 for the core season window. Uttar Pradesh, however, climbed to 5,622, the highest in six years, overtaking Punjab. 

That is why the UP belt is getting hit first. When fires rise just across Delhi’s UP flank, the smoke reaches the UP border cities before it reaches Delhi. Delhi takes the second hit. 

Gurugram, sitting on the opposite side, remains less exposed to this UP plume, so its AQI stays in a lower band. This is about where the smoke is coming from now, not where we used to think it came from.

An exclusive report from NewsDrum established that UP’s own affidavit in the Supreme Court claiming a “significant decline” in stubble burning was contradicted by ICAR bulletins, showing UP at a six-year high and its western districts turning into the season’s main hotspot. 

Today’s AQI series is the air-side mirror of that same story. The fires rose in western UP, and the dirtier air showed up first in the UP belt, then in Delhi.

Even as this shift plays out in the numbers, policy response remains reactive. With Delhi’s AQI slipping deeper into severe territory, CAQM tightened GRAP curbs across NCR, including Stage III restrictions. 

The Delhi government followed with emergency advisories asking private offices to allow 50 per cent work from home under GRAP-III.

These steps may reduce local dust, construction emissions and traffic load. But they cannot neutralise an external smoke wave that is arriving daily from the UP side. That is why Delhi is staying near severe even when Punjab and Haryana have brought their fires down.

Also read: Exclusive: Data links Punjab's fire spikes to Delhi's pollution within 24 hours

The month’s data leaves a clear conclusion. Delhi is choking because the main seasonal smoke source has shifted closer, to western Uttar Pradesh, and the daily AQI bulletins are showing that direction again and again. 

Until those UP fires fall meaningfully, NCR will keep swinging back into severe air, no matter how many emergency band-aids are announced in Delhi.

Also read: How Rekha Gupta failed PM Modi on Delhi’s toxic air

Despite clear evidence year after year, governments and agencies have avoided naming stubble burning as a major driver of Delhi’s winter pollution.

Delhi is the receiver, but the fires are in other states. If the source is officially acknowledged, those states would have to act firmly against farm burning and enforce penalties on farmers. No government wants to take that risk in an election-heavy belt.

So the public conversation is kept vague. The focus shifts to “weather conditions”, “local dust”, “vehicles”, or “construction”, because those are easier targets and do not upset rural vote banks.

Even when satellite data and AQI patterns point to a specific fire belt, the response stays indirect and defensive.

Authorities announce GRAP steps, restrict vehicles, stop construction, and advise work from home. These measures manage Delhi’s local emissions, but they sidestep the main external smoke load entering NCR.