SmogRank / India / Tamil Nadu / Perundurai

Perundurai, month by month

Perundurai has a measured daily mean on 349 days since 19 February 2025. Its worst month was December 2025, at 117 US AQI (41.8 µg/m³), 243rd of 3,006 cities on that month's world ranking. Its cleanest was October 2025, at 61 US AQI (14.4 µg/m³).

Every month since 2025

2026too few days for a mean (a year needs 200)91 days measured
Jan17 daysFeb7 daysMarnoneApr18 daysMay67#336Jun20 daysJulnoneAugnoneSepnoneOctnone
202574 for the year258 days measured222nd of 2,681 in the world
JanFeb9 daysMar72#543Apr14 daysMay66#333Jun67#284Jul63#383Aug63#314Sep66#285Oct61#366Nov20 daysDec117#243
Each square is a month's mean PM2.5 in US AQI from Perundurai's measured days, with its place on that month's world ranking under it. A month has a mean once 70% of its days are measured, the rule the monthly rankings use; under that, the square gives the days measured. Each square opens that month's ranking with Perundurai marked; each year, the year's.
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales

Months without a mean, and why

12 months
MonthWhy
Oct 2026No day measured. The others: 11 with no readings from the monitor, 1 with under 18 hours of readings or readings that failed our checks.
Sep 2026No day measured. The others: 10 with no readings from the monitor, 3 with readings for part of the day (a day needs 18 hours), 17 with under 18 hours of readings or readings that failed our checks.
Aug 2026No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Jul 2026No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Jun 202620 of 30 days measured; a month needs 21. The others: 10 with under 18 hours of readings or readings that failed our checks.
Apr 202618 of 30 days measured; a month needs 21. The others: 12 with under 18 hours of readings or readings that failed our checks.
Mar 2026No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Feb 20267 of 28 days measured; a month needs 20. The others: 21 with under 18 hours of readings or readings that failed our checks.
Jan 202617 of 31 days measured; a month needs 22. The others: 14 with under 18 hours of readings or readings that failed our checks.
Nov 202520 of 30 days measured; a month needs 21. The others: 10 with under 18 hours of readings or readings that failed our checks.
Apr 202514 of 30 days measured; a month needs 21. The others: 16 with under 18 hours of readings or readings that failed our checks.
Feb 20259 of 28 days measured; a month needs 20. The others: 1 with under 18 hours of readings or readings that failed our checks.

A day counts once 18 hours of it are measured; a month needs 70% of its days.

Perundurai's worst months

MonthUS AQIDays measuredWorld rank
December 2025 11741.8 µg/m³31 of 31243rdof 3,006
March 2025 7220.6 µg/m³31 of 31543rdof 2,862
June 2025 6717.8 µg/m³26 of 30284thof 2,508
May 2026 6717.8 µg/m³29 of 31336thof 2,874
May 2025 6617.4 µg/m³22 of 31333rdof 2,826
September 2025 6617.2 µg/m³23 of 30285thof 3,104

Monthly means over the days measured; finished months only. World rank: its place on that month's world ranking of every city with enough days. Each month opens that ranking.

Perundurai's worst days

DayUS AQI
31 Dec 2025 15764.4 µg/m³
20 Dec 2025 15460.2 µg/m³
19 Dec 2025 15357.8 µg/m³
6 Dec 2025 15257.5 µg/m³
21 Dec 2025 15257.2 µg/m³
22 Dec 2025 14955.0 µg/m³
30 Dec 2025 14754.2 µg/m³
28 Nov 2025 14653.7 µg/m³
25 Dec 2025 14051.5 µg/m³
7 Dec 2025 13951.0 µg/m³

Daily means, the highest since 19 Feb 2025; the WHO's daily guideline is 15 µg/m³. Each date opens that day's world ranking, and each episode the bad-air spell it was part of.

Use this history

SmogRank, PM2.5 monthly and daily means, Perundurai, India, 19 Feb 2025 – 22 Jun 2026. Monitor data from CPCB via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/in/perundurai/history (accessed 12 Oct 2026).

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You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.

Perundurai now: the last 24 hours, its ranks today and the last 12 months day by day.

Updated 2026-10-12 21:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index. Some low-cost readings: Sensor.Community, ODbL (data and licence). Some readings: Uzhydromet (Uzbekistan's Hydrometeorological Service); Department of Environment, Nepal; Vietnam's government monitors; Aurassure; Umhverfisstofnun (Environment Agency of Iceland); RMCAB (Secretaría Distrital de Ambiente, Bogotá); Love My Air (City and County of Denver), no reuse terms published (why we use them).