SmogRank / Episodes / India
North-eastern India, September 2026
For 6 days, from 4 to 9 September 2026, 14 cities in India and Bhutan had PM2.5 at least twice their usual for the time of year. The worst reading was Bihār Sharīf, Bihar, India: 107.0 µg/m³ on 4 September, about 2.0× its usual 52.4.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 14 in 2 countries
Days 6 4 to 9 September 2026
Worst day 6 September 8 cities counted
Furthest above usual 6.4× Sasarām
Day by day
Play 6 September 8 cities at twice their usual or more
Rānīganj Āsansol Jharia Kolkata Haldia Katihar Baripāda Rairangpur Purnia Begusarai Saharsa Kishanganj Arāria Rājgīr Joda Samāstipur Dhaka Rourkela Patna Hājīpur Siliguri Muzaffarpur Arrah Chāpra Dera Colliery Township Angul Bhubaneswar Gangtok Mothīhāri Siwān Bettiah Nalbāri Guwahati Gorakhpur Gaya Durgapur Bihār Sharīf Shrīrāmpur Cuttack Byasanagar Phuntsholing Keonjhargarh Munger Agartala Barbil Bhāgalpur Belpahar Sasarām 1 Sep 2 3 4 5 6 7 8 9 10 11 12 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
Gaya Gaya, 1 September: 53.4 µg/m³, 2.2× usual Gaya, 2 September: 10.5 µg/m³, 0.4× usual Gaya, 3 September: 61.9 µg/m³, 2.5× usual Gaya, 4 September: 32.7 µg/m³, 1.3× usual Gaya, 5 September: 26.3 µg/m³, 1.1× usual Gaya, 6 September: 29.0 µg/m³, 1.2× usual Gaya, 7 September: 28.7 µg/m³, 1.2× usual Gaya, 8 September: 49.3 µg/m³, 2.0× usual Gaya, 9 September: 24.3 µg/m³, 1.0× usual Gaya, 10 September: 22.3 µg/m³, 0.9× usual Gaya, 11 September: 23.2 µg/m³, 0.9× usual Gaya, 12 September: 22.9 µg/m³, 0.9× usual Sasarām Sasarām, 1 September: 49.8 µg/m³, 4.1× usual Sasarām, 2 September: 39.0 µg/m³, 3.3× usual Sasarām, 3 September: 56.5 µg/m³, 4.7× usual Sasarām, 4 September: 38.1 µg/m³, 3.2× usual Sasarām, 5 September: 28.9 µg/m³, 2.4× usual Sasarām, 6 September: 63.7 µg/m³, 5.3× usual Sasarām, 7 September: 35.6 µg/m³, 3.0× usual Sasarām, 8 September: no reading Sasarām, 9 September: 76.8 µg/m³, 6.4× usual Sasarām, 10 September: no reading Sasarām, 11 September: no reading Sasarām, 12 September: 11.4 µg/m³, 1.0× usual Bhāgalpur Bhāgalpur, 1 September: 44.8 µg/m³, 1.7× usual Bhāgalpur, 2 September: 74.2 µg/m³, 2.9× usual Bhāgalpur, 3 September: 72.2 µg/m³, 2.8× usual Bhāgalpur, 4 September: 82.9 µg/m³, 3.2× usual Bhāgalpur, 5 September: 80.8 µg/m³, 3.1× usual Bhāgalpur, 6 September: 89.8 µg/m³, 3.5× usual Bhāgalpur, 7 September: no reading Bhāgalpur, 8 September: 37.2 µg/m³, 1.4× usual Bhāgalpur, 9 September: 41.3 µg/m³, 1.6× usual Bhāgalpur, 10 September: 50.5 µg/m³, 2.0× usual Bhāgalpur, 11 September: 25.6 µg/m³, 1.0× usual Bhāgalpur, 12 September: 24.7 µg/m³, 1.0× usual Byasanagar Byasanagar, 1 September: no reading Byasanagar, 2 September: 43.8 µg/m³, 2.4× usual Byasanagar, 3 September: 39.2 µg/m³, 2.2× usual Byasanagar, 4 September: 31.6 µg/m³, 1.8× usual Byasanagar, 5 September: 34.3 µg/m³, 1.9× usual Byasanagar, 6 September: 34.7 µg/m³, 1.9× usual Byasanagar, 7 September: 32.3 µg/m³, 1.8× usual Byasanagar, 8 September: 41.0 µg/m³, 2.3× usual Byasanagar, 9 September: 32.6 µg/m³, 1.8× usual Byasanagar, 10 September: 17.8 µg/m³, 1.0× usual Byasanagar, 11 September: 14.8 µg/m³, 0.8× usual Byasanagar, 12 September: 25.7 µg/m³, 1.4× usual Keonjhargarh Keonjhargarh, 1 September: no reading Keonjhargarh, 2 September: 33.7 µg/m³, 2.5× usual Keonjhargarh, 3 September: 14.9 µg/m³, 1.1× usual Keonjhargarh, 4 September: 18.2 µg/m³, 1.3× usual Keonjhargarh, 5 September: 30.3 µg/m³, 2.2× usual Keonjhargarh, 6 September: 25.3 µg/m³, 1.9× usual Keonjhargarh, 7 September: 34.8 µg/m³, 2.6× usual Keonjhargarh, 8 September: 25.7 µg/m³, 1.9× usual Keonjhargarh, 9 September: 28.5 µg/m³, 2.1× usual Keonjhargarh, 10 September: 20.6 µg/m³, 1.5× usual Keonjhargarh, 11 September: 18.1 µg/m³, 1.3× usual Keonjhargarh, 12 September: 22.0 µg/m³, 1.6× usual Bihār Sharīf Bihār Sharīf, 1 September: no reading Bihār Sharīf, 2 September: no reading Bihār Sharīf, 3 September: 93.8 µg/m³, 1.8× usual Bihār Sharīf, 4 September: 107.0 µg/m³, 2.0× usual Bihār Sharīf, 5 September: 12.5 µg/m³, 0.2× usual Bihār Sharīf, 6 September: no reading Bihār Sharīf, 7 September: no reading Bihār Sharīf, 8 September: 17.8 µg/m³, 0.3× usual Bihār Sharīf, 9 September: 14.2 µg/m³, 0.3× usual Bihār Sharīf, 10 September: 7.4 µg/m³, 0.1× usual Bihār Sharīf, 11 September: no reading Bihār Sharīf, 12 September: no reading Belpahar Belpahar, 1 September: 15.5 µg/m³, 1.1× usual Belpahar, 2 September: 13.7 µg/m³, 1.0× usual Belpahar, 3 September: 16.8 µg/m³, 1.2× usual Belpahar, 4 September: 56.9 µg/m³, 4.2× usual Belpahar, 5 September: 35.6 µg/m³, 2.6× usual Belpahar, 6 September: 52.4 µg/m³, 3.9× usual Belpahar, 7 September: 55.2 µg/m³, 4.1× usual Belpahar, 8 September: 66.8 µg/m³, 4.9× usual Belpahar, 9 September: 53.3 µg/m³, 3.9× usual Belpahar, 10 September: 11.1 µg/m³, 0.8× usual Belpahar, 11 September: 6.3 µg/m³, 0.5× usual Belpahar, 12 September: 9.0 µg/m³, 0.7× usual Agartala Agartala, 1 September: 21.7 µg/m³, 2.0× usual Agartala, 2 September: 22.7 µg/m³, 2.1× usual Agartala, 3 September: 23.3 µg/m³, 2.2× usual Agartala, 4 September: 29.8 µg/m³, 2.8× usual Agartala, 5 September: 29.6 µg/m³, 2.8× usual Agartala, 6 September: 30.1 µg/m³, 2.8× usual Agartala, 7 September: 34.2 µg/m³, 3.2× usual Agartala, 8 September: 35.9 µg/m³, 3.4× usual Agartala, 9 September: 28.9 µg/m³, 2.7× usual Agartala, 10 September: 24.4 µg/m³, 2.3× usual Agartala, 11 September: 23.2 µg/m³, 2.2× usual Agartala, 12 September: 23.3 µg/m³, 2.2× usual Munger Munger, 1 September: no reading Munger, 2 September: no reading Munger, 3 September: no reading Munger, 4 September: no reading Munger, 5 September: 59.8 µg/m³, 2.6× usual Munger, 6 September: no reading Munger, 7 September: 22.8 µg/m³, 1.0× usual Munger, 8 September: 19.4 µg/m³, 0.9× usual Munger, 9 September: no reading Munger, 10 September: no reading Munger, 11 September: no reading Munger, 12 September: 15.0 µg/m³, 0.7× usual Shrīrāmpur Shrīrāmpur, 1 September: 20.6 µg/m³, 1.2× usual Shrīrāmpur, 2 September: 27.2 µg/m³, 1.6× usual Shrīrāmpur, 3 September: 33.8 µg/m³, 2.0× usual Shrīrāmpur, 4 September: 28.3 µg/m³, 1.7× usual Shrīrāmpur, 5 September: 36.3 µg/m³, 2.1× usual Shrīrāmpur, 6 September: 34.6 µg/m³, 2.0× usual Shrīrāmpur, 7 September: 32.5 µg/m³, 1.9× usual Shrīrāmpur, 8 September: 29.9 µg/m³, 1.8× usual Shrīrāmpur, 9 September: 27.4 µg/m³, 1.6× usual Shrīrāmpur, 10 September: 20.0 µg/m³, 1.2× usual Shrīrāmpur, 11 September: 16.0 µg/m³, 0.9× usual Shrīrāmpur, 12 September: 19.1 µg/m³, 1.1× usual Durgapur Durgapur, 1 September: 14.6 µg/m³, 0.7× usual Durgapur, 2 September: 25.8 µg/m³, 1.3× usual Durgapur, 3 September: 28.6 µg/m³, 1.4× usual Durgapur, 4 September: 24.5 µg/m³, 1.2× usual Durgapur, 5 September: 32.7 µg/m³, 1.6× usual Durgapur, 6 September: 41.2 µg/m³, 2.0× usual Durgapur, 7 September: 26.7 µg/m³, 1.3× usual Durgapur, 8 September: 29.6 µg/m³, 1.5× usual Durgapur, 9 September: 29.5 µg/m³, 1.5× usual Durgapur, 10 September: 12.0 µg/m³, 0.6× usual Durgapur, 11 September: 12.2 µg/m³, 0.6× usual Durgapur, 12 September: 17.2 µg/m³, 0.8× usual Barbil Barbil, 1 September: 22.9 µg/m³, 1.4× usual Barbil, 2 September: 31.6 µg/m³, 1.9× usual Barbil, 3 September: 9.3 µg/m³, 0.6× usual Barbil, 4 September: 30.5 µg/m³, 1.8× usual Barbil, 5 September: 21.1 µg/m³, 1.3× usual Barbil, 6 September: 34.6 µg/m³, 2.1× usual Barbil, 7 September: 53.3 µg/m³, 3.2× usual Barbil, 8 September: 35.4 µg/m³, 2.1× usual Barbil, 9 September: 31.3 µg/m³, 1.9× usual Barbil, 10 September: 21.4 µg/m³, 1.3× usual Barbil, 11 September: 9.4 µg/m³, 0.6× usual Barbil, 12 September: 13.7 µg/m³, 0.8× usual Phuntsholing Phuntsholing, 1 September: 1.4 µg/m³, 0.1× usual Phuntsholing, 2 September: 3.0 µg/m³, 0.3× usual Phuntsholing, 3 September: 5.2 µg/m³, 0.5× usual Phuntsholing, 4 September: 10.1 µg/m³, 0.9× usual Phuntsholing, 5 September: 24.2 µg/m³, 2.1× usual Phuntsholing, 6 September: 29.9 µg/m³, 2.6× usual Phuntsholing, 7 September: 27.2 µg/m³, 2.4× usual Phuntsholing, 8 September: 41.6 µg/m³, 3.6× usual Phuntsholing, 9 September: 35.3 µg/m³, 3.1× usual Phuntsholing, 10 September: 21.3 µg/m³, 1.9× usual Phuntsholing, 11 September: 10.5 µg/m³, 0.9× usual Phuntsholing, 12 September: 8.7 µg/m³, 0.8× usual Cuttack Cuttack, 1 September: 20.1 µg/m³, 1.1× usual Cuttack, 2 September: 22.8 µg/m³, 1.3× usual Cuttack, 3 September: 16.4 µg/m³, 0.9× usual Cuttack, 4 September: 26.1 µg/m³, 1.5× usual Cuttack, 5 September: 19.4 µg/m³, 1.1× usual Cuttack, 6 September: 17.2 µg/m³, 1.0× usual Cuttack, 7 September: 19.7 µg/m³, 1.1× usual Cuttack, 8 September: 27.0 µg/m³, 1.5× usual Cuttack, 9 September: 40.7 µg/m³, 2.3× usual Cuttack, 10 September: 29.6 µg/m³, 1.7× usual Cuttack, 11 September: 11.3 µg/m³, 0.6× usual Cuttack, 12 September: 12.6 µg/m³, 0.7× usual 1 Sep 3 5 7 9 11 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
Sasarām Bihar, India 5 9 September 12.0 6.4× Belpahar Odisha, India 6 8 September 13.5 4.9× Phuntsholing Chukha, Bhutan 1 8 September 11.4 3.6× Bhāgalpur Bihar, India 3 6 September 25.8 3.5× Agartala Tripura, India 2 8 September 10.7 3.4× Barbil Odisha, India 3 7 September 16.8 3.2× Munger Bihar, India 1 5 September 22.6 2.6× Keonjhargarh Odisha, India 3 7 September 13.6 2.6× Gaya Bihar, India 1 3 September 24.6 2.5× Byasanagar Odisha, India 1 2 September 17.9 2.4× Cuttack Odisha, India 1 9 September 17.7 2.3× Shrīrāmpur West Bengal, India 2 5 September 17.0 2.1× Bihār Sharīf Bihar, India 1 4 September 52.4 2.0× Durgapur West Bengal, India 1 6 September 20.3 2.0×
Daily means in µg/m³. Usual: the city's median for this time of year (its days within 21 days of the date, every year, leaving out the week around it). Above usual: its highest day against that.
Against other episodes in India and Bhutan
Number 2 of 5 episodes in India and Bhutan since our records began, by cities reached.
Bars: cities reached; colour: the level of the episode's highest daily reading.
Use this page SmogRank, North-eastern India, September 2026: 14 cities with PM2.5 at twice their usual or more, 4 to 9 September 2026, smogrank.com/episodes/2026-09-north-eastern-india (accessed 2 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.
