Zero Good Air Days: 9 Years of Delhi November AQI Data

Zero. Out of 7,936 station-level AQI readings recorded during November in Delhi between 2016 and 2024, that is how many fell into the "Good" category. Not a handful. Not a dozen. Literally zero.

39 monitoring stations. 270 station-days. Nine consecutive Novembers. And not once did any CPCB monitor anywhere in Delhi register air clean enough to be called Good.

That number stopped us when we ran the query. So we pulled every November reading in the CPCB database and built this complete picture of what happens to Delhi's air when October ends.

The September-to-November Cliff

It does not creep up. It hits like a wall.

September 2024 averaged 105 AQI across Delhi's monitors. Unpleasant but livable. Two months later, the citywide average was 372. A 3.5x jump. And this happens every single year.

2021 stands out. September was the cleanest it had been in years at just 78 AQI. Then November exploded to 377. A 4.8x swing. Stubble burning that year peaked earlier than usual, and stagnant wind patterns trapped pollutants across the Indo-Gangetic Plain for weeks.

The pattern holds even when September improves. Between 2019 and 2024, September AQI stayed flat around 100-105. November went from 312 to 372. The problem is getting worse at the wrong end.

Nine Novembers, Not a Single Good One

The mildest November on record was 2019, averaging 312 AQI. Still Very Poor. That year, the monsoon extended well into October, pushing the pollution season start later than usual. Even then, 24% of all readings crossed into Severe.

The last three years are more concerning. After a dip in 2022 (321), the average climbed right back to 372-373 in 2023 and 2024. With 37-38 stations now active, sampling bias is not the issue. This is the number.

Delhi's annual average AQI has trended down slightly over the decade, from 252 in 2016 to 210 in 2024. Cleaner summers are driving that improvement. November refuses to participate.

How Delhi Spends November: Category Breakdown

The averages tell one story. The distribution tells a darker one.

Every November reading was classified into CPCB's AQI categories. "Moderate or better" here means anything at or below 200, which most countries would themselves consider unhealthy.

Three things jump out.

2021 and 2024 had zero readings even reaching Moderate. For the entire month, across every station, every single day registered Poor or worse.

2022 looked like a good year by Delhi November standards. "Only" 14% Severe, the lowest in the dataset. But 48% was still Very Poor. The "better" November just shifted readings from Severe to Poor. That is what passes for progress.

2023 was brutal at the top end. 41% of all readings crossed into Severe (above 400 AQI). Almost every other reading was Very Poor. Barely anything below 300.

What Diwali Actually Does to the Numbers

The cracker debate returns every year. So does the same question: how much of November's pollution comes from Diwali, and how much was already there?

The data shows a clear day-after spike. In almost every year, the citywide average AQI on the day after Diwali jumped significantly. But the pre-Diwali baseline matters more than the jump itself.

The highest reading almost never lands on Diwali itself. It comes one or two days later. Firecracker emissions mix with existing particulate matter, and the winter temperature inversion traps everything close to the ground for 24-48 hours before dispersal begins.

2021 was the worst post-Diwali spike on record: 462 average AQI on November 5, the day after. That is not a single hotspot reading. It is a citywide average across 38 stations. At that level, the recommended advice is to stay indoors with air purifiers running.

2023 is telling because Diwali day itself (November 12) clocked a relatively low 218. One day later, AQI hit 358, a 64% jump. Wind speeds dropped to near zero that week, creating a textbook pollution trap.

But here is the uncomfortable truth: the day before Diwali 2024 already registered 328 AQI, firmly Very Poor. Crackers pushed it higher. The air was already dangerous before a single patakha was lit.

The Station Lottery in November

In normal months, where you live in Delhi makes a real difference. South Delhi stations near Lodhi Garden can read 50-70 AQI points lower than industrial zones like Anand Vihar.

November erases that gap. Even the "best" station in November 2024, Lodhi Road IITM, averaged 286. That is Poor by CPCB standards. The worst, Anand Vihar, hit 414.

The top 10 worst stations span every direction. Anand Vihar (East), Bawana (Northwest), Rohini (North), Nehru Nagar (Central), Punjabi Bagh (West). November pollution is not a localized industrial problem. It blankets the entire city.

Nine of the ten averaged above 400, which triggers GRAP Stage IV, the highest emergency level. Construction bans, truck restrictions, office closures. The fact that this is a month-long average, not a daily spike, tells you GRAP is essentially meant to be active all of November.

7,936 Readings, One Story

Combine all 7,936 November readings from 2016 to 2024 and the picture is blunt.

Half of all readings sit in Very Poor territory (301-400 AQI). Another quarter is Severe, above 400. Together, nearly 74% of everything Delhi breathed in November was in the two worst categories. The Satisfactory slice is barely visible at 0.7%, almost entirely from 2019's unusually late pollution season.

November vs India's Own Air Quality Standard

India's National Ambient Air Quality Standard targets a PM2.5 annual average that translates to roughly AQI 100. November 2024 alone averaged 373 across Delhi's monitors. That is 3.7 times the national standard.

Under the National Clean Air Programme (NCAP), Delhi was supposed to reduce PM2.5 by 40% from 2017 baseline levels by 2025-26. The November numbers went from 368 in 2017 to 373 in 2024. That is not a 40% reduction. It is a slight increase.

The rest of the year did improve. Annual averages dropped from 249 in 2017 to 210 in 2024, a 16% cut driven by cleaner monsoons and post-monsoon months. But November pollution is now 1.9x the rest-of-year average, up from 1.5x in 2016. The seasonal gap is widening, not closing.

What This Means

Three crore people breathe this air every November. Schools shut for "pollution holidays." Courts intervene because executive action falls short. GRAP protocols activate, then quietly roll back before the month ends.

Nine years of CPCB readings confirm one thing. Delhi's November is broken, and relative to the rest of the year, it is getting worse.

If you are in Delhi or NCR during November, an air purifier is not optional. For station-level analysis of Delhi's most and least polluted areas, check our detailed neighbourhood ranking. For practical steps to cut your exposure, read our air pollution protection guide. And to track live AQI from your nearest station, visit the Delhi air quality page.