SmogRank / Episodes / India

Tamil Nadu and Karnataka, India, August 2025

For 2 days, from 28 to 29 August 2025, 9 cities in India had PM2.5 at least twice their usual for the time of year. The worst reading was Nagapattinam, Tamil Nadu, India: 171.0 µg/m³ on 29 August, about 3.1× its usual 55.3. Ended 29 August.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached9in 1 country
Days228 to 29 August 2025
Worst day29 August6 cities counted
Furthest above usual4.4×Cuddalore

Day by day

29 August 6 cities at twice their usual or more
PerunduraiTiruppurKarurCoimbatoreSalemDindigulGudalurTiruchirappalliNavalpattuThrissurAriyalūrClosepetAlangadBengaluruMadikeriTumkūrChik BallāpurKannurVellorePuducherryTirunelveliKollamRānipetChittoorChikmagalūrGūduvāncheriChennaiGummidipundiRamanathapuramMangaluruKanchipuramOotyNeelankaraiNilaiyūrTirupparangunramNagapattinamCuddalore
25 Aug2627282930311 Sep
Every measured city in the area, coloured by its PM2.5 that day; a dark ring marks a city at twice its usual or more. Bars: cities counted each day, coloured by their median level. Choose a day or press play; without JavaScript, the days link to that day's world ranking.

How it spread

CuddaloreCuddalore, 25 August: 102.0 µg/m³Cuddalore, 26 August: 81.2 µg/m³Cuddalore, 27 August: 13.8 µg/m³Cuddalore, 28 August: 123.0 µg/m³, 3.4× its usual 36.1Cuddalore, 29 August: 161.0 µg/m³, 4.4× its usual 36.9Cuddalore, 30 August: no readingCuddalore, 31 August: 73.8 µg/m³Cuddalore, 1 September: 143.0 µg/m³TirupparangunramTirupparangunram, 25 August: 32.5 µg/m³Tirupparangunram, 26 August: 14.5 µg/m³Tirupparangunram, 27 August: 36.2 µg/m³Tirupparangunram, 28 August: 89.8 µg/m³, 3.0× its usual 29.5Tirupparangunram, 29 August: 11.5 µg/m³Tirupparangunram, 30 August: 17.3 µg/m³Tirupparangunram, 31 August: 11.0 µg/m³Tirupparangunram, 1 September: 17.0 µg/m³NilaiyūrNilaiyūr, 25 August: 32.5 µg/m³Nilaiyūr, 26 August: 14.5 µg/m³Nilaiyūr, 27 August: 36.2 µg/m³Nilaiyūr, 28 August: 89.8 µg/m³, 3.0× its usual 29.5Nilaiyūr, 29 August: 11.5 µg/m³Nilaiyūr, 30 August: 17.3 µg/m³Nilaiyūr, 31 August: 11.0 µg/m³Nilaiyūr, 1 September: 17.0 µg/m³NeelankaraiNeelankarai, 25 August: 23.6 µg/m³Neelankarai, 26 August: 24.1 µg/m³Neelankarai, 27 August: 19.6 µg/m³Neelankarai, 28 August: 53.0 µg/m³, 3.0× its usual 17.4Neelankarai, 29 August: 16.4 µg/m³Neelankarai, 30 August: 19.1 µg/m³Neelankarai, 31 August: 38.3 µg/m³Neelankarai, 1 September: 17.0 µg/m³NagapattinamNagapattinam, 25 August: no readingNagapattinam, 26 August: 59.4 µg/m³Nagapattinam, 27 August: no readingNagapattinam, 28 August: no readingNagapattinam, 29 August: 171.0 µg/m³, 3.1× its usual 55.3Nagapattinam, 30 August: 11.9 µg/m³Nagapattinam, 31 August: 90.9 µg/m³Nagapattinam, 1 September: 127.0 µg/m³RamanathapuramRamanathapuram, 25 August: 33.3 µg/m³Ramanathapuram, 26 August: 45.9 µg/m³Ramanathapuram, 27 August: 29.5 µg/m³Ramanathapuram, 28 August: 29.9 µg/m³Ramanathapuram, 29 August: 81.2 µg/m³, 2.2× its usual 36.6Ramanathapuram, 30 August: 58.3 µg/m³Ramanathapuram, 31 August: 35.8 µg/m³Ramanathapuram, 1 September: no readingOotyOoty, 25 August: no readingOoty, 26 August: 17.4 µg/m³Ooty, 27 August: 11.0 µg/m³Ooty, 28 August: 7.3 µg/m³Ooty, 29 August: 75.4 µg/m³, 2.9× its usual 25.7Ooty, 30 August: no readingOoty, 31 August: no readingOoty, 1 September: 134.0 µg/m³KanchipuramKanchipuram, 25 August: 28.0 µg/m³Kanchipuram, 26 August: 35.5 µg/m³Kanchipuram, 27 August: 34.7 µg/m³Kanchipuram, 28 August: 20.4 µg/m³Kanchipuram, 29 August: 60.8 µg/m³, 2.7× its usual 22.6Kanchipuram, 30 August: 64.1 µg/m³Kanchipuram, 31 August: 82.6 µg/m³Kanchipuram, 1 September: 69.8 µg/m³MangaluruMangaluru, 25 August: 35.5 µg/m³Mangaluru, 26 August: 27.3 µg/m³Mangaluru, 27 August: 19.7 µg/m³Mangaluru, 28 August: 22.4 µg/m³Mangaluru, 29 August: 51.2 µg/m³, 2.6× its usual 20.0Mangaluru, 30 August: 105.0 µg/m³Mangaluru, 31 August: 45.7 µg/m³Mangaluru, 1 September: 27.1 µg/m³25 Aug2627282930311 Sep
Every counted city, in the order the episode reached them, 3 days before to 3 after. Each square is a day, coloured by that day's PM2.5; outlined: at twice the city's usual or more.
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

Every city it reached

CityDaysHighestUsualAbove usual
CuddaloreTamil Nadu, India2 161.029 August36.94.4×
NagapattinamTamil Nadu, India1 171.029 August55.33.1×
TirupparangunramTamil Nadu, India1 89.828 August29.53.0×
NilaiyūrTamil Nadu, India1 89.828 August29.53.0×
NeelankaraiTamil Nadu, India1 53.028 August17.43.0×
OotyTamil Nadu, India1 75.429 August25.72.9×
KanchipuramTamil Nadu, India1 60.829 August22.62.7×
MangaluruKarnataka, India1 51.229 August20.02.6×
RamanathapuramTamil Nadu, India1 81.229 August36.62.2×

Daily means in µg/m³, over the days each city counted in this episode. Highest: its highest of those days. Usual: the city's median for the time of year of that day (its days within 21 days of the date, every year, leaving out the week around it). Above usual: its highest day against that, with a usual under 5 µg/m³ taken as 5.

Against other episodes in India

Number 50 of 61 episodes in India since our records began, by cities reached.

Bars: cities reached; colour: the level of the episode's highest daily reading. All 61.

Use this page

SmogRank, Tamil Nadu and Karnataka, India, August 2025: 9 cities with PM2.5 at twice their usual or more, 28 to 29 August 2025, smogrank.com/episodes/2025-08-tamil-nadu-and-karnataka-india (accessed 5 October 2026).

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You're welcome to reuse a single chart, image or figure with this citation and a link. Terms.

An episode is a run of days when many cities close to each other (four or more within 350 km on a day, 8 or more in all) each had a daily PM2.5 mean of at least 25 µg/m³ and at least 2 times their usual for that time of year. Found in our own measurements, not picked by hand. How we find episodes. Values are each city's daily mean of its own monitors; causes are the usual kinds for a pattern like this, not a confirmed source.