SmogRank / Episodes / India
Eastern India, 28 September to 1 October 2026
For 4 days, from 28 September to 1 October 2026, 15 cities in India had PM2.5 at least twice their usual for the time of year. The worst reading was Dera Colliery Township, Odisha, India: 85.3 µg/m³ on 1 October, about 2.1× its usual 40.4. Readings stopped after 1 October, when 464 monitors in India went silent, so this episode may have run longer.
Likely smoke from fires Fires were detected within 300 km of the city on 75% of the counted city-days. Satellites see crop, field and forest fires alike, so this doesn't say which burned.
Cities reached 15 in 1 country
Days 4 28 September to 1 October 2026
Worst day 1 October 13 cities counted
Furthest above usual 4.7× Bhelai
Day by day
Play 1 October 13 cities at twice their usual or more
Āsansol Rānīganj Durgapur Jharia Rairangpur Baripāda Bhāgalpur Munger Katihar Rājgīr Barbil Joda Bihār Sharīf Gaya Saharsa Rourkela Samāstipur Byasanagar Patna Hājīpur Kishanganj Muzaffarpur Arrah Chāpra Angul Dhaka Siwān Varanasi Bilāspur Kahi Kuchi Nalbāri Guwahati Dispur Jājang Haldia Arāria Dera Colliery Township Keonjhargarh Purnia Kolkata Agartala Shrīrāmpur Belpahar Begusarai Koīra Sasarām Durena Bhelai 25 Sep 26 27 28 29 30 1 Oct 2 3 4 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
Bhelai Bhelai, 25 September: 7.1 µg/m³ Bhelai, 26 September: 8.1 µg/m³ Bhelai, 27 September: no reading Bhelai, 28 September: 47.0 µg/m³, 4.7× its usual 10.0 Bhelai, 29 September: 24.3 µg/m³ Bhelai, 30 September: 29.5 µg/m³, 3.0× its usual 10.0 Bhelai, 1 October: 35.5 µg/m³, 3.6× its usual 10.0 Bhelai, 2 October: no reading Bhelai, 3 October: no reading Bhelai, 4 October: no reading Durena Durena, 25 September: 7.1 µg/m³ Durena, 26 September: 8.1 µg/m³ Durena, 27 September: no reading Durena, 28 September: 47.0 µg/m³, 4.7× its usual 10.0 Durena, 29 September: 24.3 µg/m³ Durena, 30 September: 29.5 µg/m³, 3.0× its usual 10.0 Durena, 1 October: 35.5 µg/m³, 3.6× its usual 10.0 Durena, 2 October: no reading Durena, 3 October: no reading Durena, 4 October: no reading Haldia Haldia, 25 September: 9.5 µg/m³ Haldia, 26 September: 12.1 µg/m³ Haldia, 27 September: 22.9 µg/m³ Haldia, 28 September: 41.1 µg/m³, 2.0× its usual 20.1 Haldia, 29 September: 41.4 µg/m³, 2.0× its usual 20.2 Haldia, 30 September: 43.8 µg/m³, 2.1× its usual 20.6 Haldia, 1 October: 42.6 µg/m³, 2.1× its usual 20.6 Haldia, 2 October: no reading Haldia, 3 October: no reading Haldia, 4 October: no reading Keonjhargarh Keonjhargarh, 25 September: 18.4 µg/m³ Keonjhargarh, 26 September: 20.6 µg/m³ Keonjhargarh, 27 September: 26.9 µg/m³ Keonjhargarh, 28 September: 35.5 µg/m³, 2.5× its usual 14.1 Keonjhargarh, 29 September: 19.3 µg/m³ Keonjhargarh, 30 September: 31.2 µg/m³, 2.1× its usual 14.6 Keonjhargarh, 1 October: 34.5 µg/m³, 2.3× its usual 14.8 Keonjhargarh, 2 October: no reading Keonjhargarh, 3 October: no reading Keonjhargarh, 4 October: no reading Sasarām Sasarām, 25 September: 12.0 µg/m³ Sasarām, 26 September: 20.0 µg/m³ Sasarām, 27 September: 33.0 µg/m³ Sasarām, 28 September: 33.8 µg/m³, 2.4× its usual 14.3 Sasarām, 29 September: 48.5 µg/m³, 3.8× its usual 12.9 Sasarām, 30 September: 41.1 µg/m³, 3.2× its usual 12.9 Sasarām, 1 October: 58.2 µg/m³, 4.5× its usual 12.9 Sasarām, 2 October: no reading Sasarām, 3 October: no reading Sasarām, 4 October: no reading Begusarai Begusarai, 25 September: no reading Begusarai, 26 September: 11.4 µg/m³ Begusarai, 27 September: 25.9 µg/m³ Begusarai, 28 September: 32.1 µg/m³, 2.7× its usual 11.8 Begusarai, 29 September: 35.8 µg/m³, 3.0× its usual 11.8 Begusarai, 30 September: 37.6 µg/m³, 3.2× its usual 11.8 Begusarai, 1 October: 41.5 µg/m³, 3.5× its usual 11.8 Begusarai, 2 October: no reading Begusarai, 3 October: no reading Begusarai, 4 October: no reading Koīra Koīra, 25 September: 5.4 µg/m³ Koīra, 26 September: 5.6 µg/m³ Koīra, 27 September: 15.3 µg/m³ Koīra, 28 September: 29.6 µg/m³, 2.4× its usual 12.4 Koīra, 29 September: 36.6 µg/m³, 3.0× its usual 12.1 Koīra, 30 September: no reading Koīra, 1 October: 47.1 µg/m³, 4.1× its usual 11.6 Koīra, 2 October: no reading Koīra, 3 October: no reading Koīra, 4 October: no reading Belpahar Belpahar, 25 September: 4.8 µg/m³ Belpahar, 26 September: 8.7 µg/m³ Belpahar, 27 September: 20.9 µg/m³ Belpahar, 28 September: no reading Belpahar, 29 September: 61.1 µg/m³, 2.7× its usual 22.4 Belpahar, 30 September: 74.1 µg/m³, 3.4× its usual 22.1 Belpahar, 1 October: 37.7 µg/m³ Belpahar, 2 October: no reading Belpahar, 3 October: no reading Belpahar, 4 October: no reading Kolkata Kolkata, 25 September: 12.8 µg/m³ Kolkata, 26 September: 18.4 µg/m³ Kolkata, 27 September: 35.8 µg/m³ Kolkata, 28 September: 44.5 µg/m³ Kolkata, 29 September: 60.5 µg/m³, 2.5× its usual 24.5 Kolkata, 30 September: 65.1 µg/m³, 2.6× its usual 24.9 Kolkata, 1 October: 58.5 µg/m³, 2.3× its usual 25.5 Kolkata, 2 October: no reading Kolkata, 3 October: no reading Kolkata, 4 October: no reading Purnia Purnia, 25 September: 137.0 µg/m³ Purnia, 26 September: 49.7 µg/m³ Purnia, 27 September: no reading Purnia, 28 September: no reading Purnia, 29 September: 52.5 µg/m³, 2.1× its usual 25.3 Purnia, 30 September: 63.0 µg/m³, 2.5× its usual 25.3 Purnia, 1 October: no reading Purnia, 2 October: no reading Purnia, 3 October: no reading Purnia, 4 October: no reading Agartala Agartala, 25 September: 16.2 µg/m³ Agartala, 26 September: 20.7 µg/m³ Agartala, 27 September: 28.9 µg/m³ Agartala, 28 September: 46.6 µg/m³ Agartala, 29 September: 50.4 µg/m³, 2.7× its usual 18.8 Agartala, 30 September: 52.1 µg/m³, 2.7× its usual 19.3 Agartala, 1 October: 46.1 µg/m³, 2.4× its usual 19.1 Agartala, 2 October: no reading Agartala, 3 October: no reading Agartala, 4 October: no reading Shrīrāmpur Shrīrāmpur, 25 September: 14.0 µg/m³ Shrīrāmpur, 26 September: 18.9 µg/m³ Shrīrāmpur, 27 September: no reading Shrīrāmpur, 28 September: no reading Shrīrāmpur, 29 September: 42.0 µg/m³, 2.0× its usual 21.0 Shrīrāmpur, 30 September: 51.3 µg/m³, 2.4× its usual 21.0 Shrīrāmpur, 1 October: 56.3 µg/m³, 2.7× its usual 21.0 Shrīrāmpur, 2 October: no reading Shrīrāmpur, 3 October: no reading Shrīrāmpur, 4 October: no reading Dera Colliery Towns… Dera Colliery Township, 25 September: no reading Dera Colliery Township, 26 September: 26.3 µg/m³ Dera Colliery Township, 27 September: no reading Dera Colliery Township, 28 September: 56.3 µg/m³ Dera Colliery Township, 29 September: 57.5 µg/m³ Dera Colliery Township, 30 September: 65.1 µg/m³ Dera Colliery Township, 1 October: 85.3 µg/m³, 2.1× its usual 40.4 Dera Colliery Township, 2 October: no reading Dera Colliery Township, 3 October: no reading Dera Colliery Township, 4 October: no reading Arāria Arāria, 25 September: 45.0 µg/m³ Arāria, 26 September: 46.8 µg/m³ Arāria, 27 September: 75.8 µg/m³ Arāria, 28 September: 59.2 µg/m³ Arāria, 29 September: 45.6 µg/m³ Arāria, 30 September: 58.6 µg/m³ Arāria, 1 October: 68.1 µg/m³, 2.1× its usual 32.7 Arāria, 2 October: no reading Arāria, 3 October: no reading Arāria, 4 October: no reading Jājang Jājang, 25 September: 6.0 µg/m³ Jājang, 26 September: 12.6 µg/m³ Jājang, 27 September: 19.7 µg/m³ Jājang, 28 September: 27.9 µg/m³ Jājang, 29 September: 20.8 µg/m³ Jājang, 30 September: 27.7 µg/m³ Jājang, 1 October: 31.8 µg/m³, 2.1× its usual 14.9 Jājang, 2 October: no reading Jājang, 3 October: no reading Jājang, 4 October: no reading 25 Sep 26 27 28 29 30 1 Oct 2 3 4 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. Good 0–50
Moderate 51–100
Sensitive groups 101–150
Unhealthy 151–200
Very unhealthy 201–300
Hazardous 301+
Every city it reached
City Days Highest Usual Above usual
Bhelai Chhattisgarh, India 3 28 September 10.0 4.7× Durena Chhattisgarh, India 3 28 September 10.0 4.7× Sasarām Bihar, India 4 1 October 12.9 4.5× Koīra Odisha, India 3 1 October 11.6 4.1× Begusarai Bihar, India 4 1 October 11.8 3.5× Belpahar Odisha, India 2 30 September 22.1 3.4× Shrīrāmpur West Bengal, India 3 1 October 21.0 2.7× Agartala Tripura, India 3 30 September 19.3 2.7× Kolkata West Bengal, India 3 30 September 24.9 2.6× Purnia Bihar, India 2 30 September 25.3 2.5× Keonjhargarh Odisha, India 3 28 September 14.1 2.5× Dera Colliery Township Odisha, India 1 1 October 40.4 2.1× Arāria Bihar, India 1 1 October 32.7 2.1× Haldia West Bengal, India 4 30 September 20.6 2.1× Jājang Odisha, India 1 1 October 14.9 2.1×
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 21 of 61 episodes in India since our records began, by cities reached.
India and Pakistan, October 2025 178 Western India and Pakistan, September 2026 59 North-western India, 9 to 20 July 2026 53 Northern India, March and April 2025 52 Northern India and Pakistan, June 2025 49 North-western India, November 2025 29 North-western India and Pakistan, April and May 2025 27 North-western India, 21 to 29 April 2026 26 North-western India and Pakistan, March 2026 26 Northern India, July 2025 25 North-eastern India, July 2026 23 North-western India, 15 to 16 May 2025 23 Eastern India, 28 September to 1 October 2026 15 Bars: cities reached; colour: the level of the episode's highest daily reading. All 61 .
Use this page SmogRank, Eastern India, 28 September to 1 October 2026: 15 cities with PM2.5 at twice their usual or more, 28 September to 1 October 2026, smogrank.com/episodes/2026-09-28-eastern-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. Fire detections from NASA FIRMS; smoke maps from NOAA HMS.
