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Delhi Logs Best October Air Quality in Eight Years at AQI 166

Delhi's average air quality index for October 2026 came in at 166, the capital's cleanest October in eight years, with 220 good to moderate days so far.

By Published · 2 min read
Delhi Logs Best October Air Quality in Eight Years at AQI 166 — GK24 title card

Why in News

On 31 October 2026 the Ministry of Environment, Forest and Climate Change released Delhi's air quality record for the month, showing a monthly average AQI of 166, the capital's lowest October average in eight years, along with 220 'Good to Moderate' days in 2026 up to the end of October.

The Union Ministry of Environment, Forest and Climate Change reported on 31 October 2026 that the national capital has just finished its cleanest October in nearly a decade. Delhi's monthly average Air Quality Index for October 2026 settled at 166, the lowest figure for that month in the last eight years.

How this October compares

Every one of the preceding eight Octobers was dirtier. The monthly average stood at 223 last year and climbed as high as 269 in 2018, which makes the 2026 reading a clear break from the pattern of late-autumn smog that usually settles over the city once harvesting and the festival weeks begin.

YearOctober average AQI
2026166
2025223
2024234
2023219
2022210
2021173
2020265
2019234
2018269

The ten-month picture

Taken over 1 January to 31 October, Delhi's average works out to 167 this year, better than the 170 of last year and far better than the 201 recorded in 2018. Particulate pollution has eased along with it. Average PM2.5 between 1 January and 29 October measured 69 micrograms per cubic metre, against 72 a year earlier and 93 in 2018. Coarser dust, measured as PM10, averaged 171 micrograms per cubic metre over the same stretch.

More breathable days

The count of clean days tells the same story. Between January and October the city logged 220 days in the 'Good to Moderate' band, meaning a daily average below 200 on the index. That is the largest number since 2018, leaving aside the lockdown year of 2020, when 224 such days were counted. Days in the 'Poor to Severe+' band, above 200 on the index, fell to 84 from 104 in each of the two previous years.

Who watches the air

The Commission for Air Quality Management in the National Capital Region and Adjoining Areas, known by its initials CAQM, handles the prevention, control and abatement work with the agencies concerned. It has said the effort will be intensified to improve the air further across Delhi-NCR in the days ahead.

Important Facts

Month reportedOctober 2026
Delhi's October 2026 average AQI166 (lowest for October in eight years)
October 2025 average AQI223
Average AQI, 1 Jan to 31 Oct 2026167
Average PM2.5, 1 Jan to 29 Oct 202669 micrograms per cubic metre
Average PM10, 1 Jan to 29 Oct 2026171 micrograms per cubic metre
'Good to Moderate' days, Jan-Oct 2026220
'Poor to Severe+' days, Jan-Oct 202684
Nodal commissionCAQM, for the National Capital Region and Adjoining Areas
MinistryEnvironment, Forest and Climate Change

Exam Point of View

Remember the headline figures: October 2026 average AQI 166 (lowest in eight years), January to October average 167, PM2.5 at 69 and PM10 at 171 micrograms per cubic metre, 220 good-to-moderate days and 84 poor-to-severe+ days. Also remember that a daily average below 200 on the index is counted 'Good to Moderate' here, and that CAQM is the statutory body for air quality in Delhi-NCR.

Practice Questions

Q3.EnvironmentMedium

What was Delhi's average PM2.5 concentration between 1 January and 29 October 2026?

  1. A.69 micrograms per cubic metre
  2. B.72 micrograms per cubic metre
  3. C.83 micrograms per cubic metre
  4. D.93 micrograms per cubic metre
Show answer
Correct answer: A. 69 micrograms per cubic metre

For the stretch from 1 January to 29 October 2026 the average concentration of fine particulate matter, PM2.5, in Delhi's air worked out to 69 micrograms per cubic metre, the lowest of the years compared.

Frequently Asked Questions

What was Delhi's average AQI in October 2026?

It was 166, the lowest monthly average for October in the last eight years. The comparable figure was 223 in October 2025, 234 in October 2024 and 269 in October 2018.

How many clean air days did Delhi have in 2026 up to October?

220 days fell in the 'Good to Moderate' band, meaning a daily average below 200 on the index. That is the highest count since 2018, except for 2020, when 224 such days were recorded.

Which body coordinates air quality action in Delhi-NCR?

The Commission for Air Quality Management in the National Capital Region and Adjoining Areas, or CAQM, which works with the agencies concerned on preventing, controlling and abating air pollution.

Sources

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