City report · Bihar, India
Siwān Air quality today
Air quality in Siwān currently reads AQI 192 (Unhealthy): Everyone should limit long outdoor exertion; sensitive groups more so.
AQI 192
Air quality right now
Unhealthy
- PM2.5, fine particles (µg/m³)
- 114.0
- tree cover
- 28.0%
- trees in this area
- 88.0K
- more trees needed
- 37.7K
Measured across a 2 km radius around Kagzi Muhalla, Siwan, Bihar 841226, India (12.57 km²), from a satellite image of Oct 26, 2026. Lower AQI is better: 0–50 is Good, above 300 is Hazardous.
Siwān · AQI 192 (Unhealthy)
Siwān's tree count comes to 87,965 trees across 12.57 km², 12 points below the 40% tree-cover level considered healthy for this area, so roughly 37,699 more trees would close the gap.
Air quality detail
Air quality in Siwān today: AQI 192, Unhealthy
Main pollutant: PM2.5 · Observed Nov 11, 21:15 local time via OpenAQ ground stations, US EPA index. Values in µg/m³.
Ground station · Chitragupta Nagar, Siwan - BSPCB, 700 m away
Health signal
Everyone should limit long outdoor exertion; sensitive groups more so.
PM2.5
114.0
PM10
182.0
NO₂
2.6
O₃
6.5
SO₂
19.6
CO
1.4
Data: OpenAQ · CPCB, Central Pollution Control Board, Government of India (GODL-India)
- Outdoor exercise
- Everyone should cut down long or hard exercise; sensitive groups should avoid it
- Windows
- Keep them closed
- Mask
- Wear an N95 outdoors
- Air purifier
- Run one
Over the last 7 days, the CAMS air-quality model put Siwān's daily AQI at 199 on average, from 165 on Nov 9 to an hourly peak of 269 on Nov 8.
This is the US EPA AQI. How it differs from India's AQI (CPCB) · The full guide
Where Siwān stands: the most polluted cities in the world right now · the cleanest
Tree cover detail
Tree cover in Siwān: Below target
28.0% tree cover against a 40% healthy-neighborhood target, across 12.57 km².
Trees in this area
87,965
Target trees
125,664
More trees needed
37,699
CO₂ if planted / yr
829.4 t
Deforestation · 2001–2025
How much forest has Siwān lost?
There was very little forest around Siwān in 2000, about 16 hectares, and about 2 hectares of it has been lost since. Only fairly dense woodland counts as forest in these maps, so scattered street and garden trees don't show up here.
2017: satellite photo from February 2017 of a 5 × 5 km area in the city center.
The worst year was 2009, when about 1 hectare of forest were lost.
Hectares of forest lost each year
Show the figures as a table
| Year | Cleared for good | Can grow back | Total |
|---|---|---|---|
| 2001 | under 1 ha | under 1 ha | under 1 ha |
| 2002 | under 1 ha | under 1 ha | under 1 ha |
| 2003 | under 1 ha | under 1 ha | under 1 ha |
| 2004 | under 1 ha | under 1 ha | under 1 ha |
| 2005 | under 1 ha | under 1 ha | under 1 ha |
| 2006 | under 1 ha | under 1 ha | under 1 ha |
| 2007 | under 1 ha | under 1 ha | under 1 ha |
| 2008 | under 1 ha | under 1 ha | under 1 ha |
| 2009 | under 1 ha | 1 ha | 1 ha |
| 2010 | under 1 ha | under 1 ha | under 1 ha |
| 2011 | under 1 ha | under 1 ha | under 1 ha |
| 2012 | under 1 ha | under 1 ha | under 1 ha |
| 2013 | under 1 ha | under 1 ha | under 1 ha |
| 2014 | under 1 ha | under 1 ha | under 1 ha |
| 2015 | under 1 ha | under 1 ha | under 1 ha |
| 2016 | under 1 ha | under 1 ha | under 1 ha |
| 2017 | under 1 ha | under 1 ha | under 1 ha |
| 2018 | under 1 ha | under 1 ha | under 1 ha |
| 2019 | under 1 ha | under 1 ha | under 1 ha |
| 2020 | under 1 ha | under 1 ha | under 1 ha |
| 2021 | under 1 ha | under 1 ha | under 1 ha |
| 2022 | under 1 ha | under 1 ha | under 1 ha |
| 2023 | under 1 ha | under 1 ha | under 1 ha |
| 2024 | under 1 ha | under 1 ha | under 1 ha |
| 2025 | under 1 ha | under 1 ha | under 1 ha |
Forest gained and lost, 2000–2020
- Forest in 2000
- 562 ha
- Forest in 2020
- 699 ha
- Overall change
- +137 hamore forest than in 2000
Comparing satellite maps from 2000 and 2020, the forest around Siwān grew from about 562 hectares to 699 hectares, a net gain of about 137 hectares (+24%). New forest grew on about 147 hectares, while 9 hectares were lost.
These 2000 and 2020 maps, from the University of Maryland, count any land with trees taller than 5 m as forest, including plantations and orchards. Forest that was cut or burned and had grown back by 2020 counts in both years, so the loss here is smaller than the yearly figures.
These figures cover everything within 10 km of the city center, a wider area than the report above, because forest is usually lost at a city's edges.
Source: Hansen/UMD/Google/USGS/NASA, Global Forest Change (GFC-2025-v1.13); causes: WRI/Google DeepMind drivers of forest loss; both CC BY 4.0, summed by Airleaf for each area. Forest gained and lost 2000–2020: Potapov et al. 2022, UMD GLAD Global Land Cover and Land Use Change, CC BY 4.0. Images: contains modified Copernicus Sentinel data. How it's measured
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Frequently asked
Questions about Siwān
What is the air quality (AQI) in Siwān right now?
The latest reading for Siwān shows an AQI of 192 (Unhealthy), measured Nov 11, 21:15 local time by the Chitragupta Nagar, Siwan - BSPCB ground monitoring station, 700 m away, via OpenAQ. The main pollutant is PM2.5. Everyone should limit long outdoor exertion; sensitive groups more so.
Is it safe to exercise outside in Siwān today?
At AQI 192 (Unhealthy): everyone should cut down long or hard exercise; sensitive groups should avoid it. Windows: keep them closed. Masks: wear an N95 outdoors. The reading changes through the day, so check again before a long run or ride.
What has the air quality in Siwān been like this week?
Over the last 7 days, the CAMS air-quality model put Siwān's daily AQI at 199 on average, from 165 on Nov 9 to an hourly peak of 269 on Nov 8. On 7 of those days the average was above 100, unhealthy for sensitive groups.
Is Siwān's AQI the same as India's AQI (CPCB)?
No. Airleaf shows the US EPA Air Quality Index (AQI), the scale used by IQAir and most air-quality apps. India's Central Pollution Control Board (CPCB) publishes the National Air Quality Index on its own scale: 0–50 good, 51–100 satisfactory, 101–200 moderate, 201–300 poor, 301–400 very poor and 401–500 severe. The two scales don't line up. At moderate fine-particle levels the US scale reads higher: 55 µg/m³ of PM2.5 is 149 on the US AQI but about 92, "satisfactory", on India's. In heavy smog India's reads higher: 100 µg/m³ is 182 on the US AQI and about 232, "poor", on India's. CPCB also averages particles over 24 hours, so its figure moves more slowly than an hourly reading.
How much forest has the area around Siwān lost since 2001?
There was very little forest around Siwān in 2000, about 16 hectares, and about 2 hectares of it has been lost since. Only fairly dense woodland counts as forest in these maps, so scattered street and garden trees don't show up here. Comparing satellite maps from 2000 and 2020, the forest around Siwān grew from about 562 hectares to 699 hectares, a net gain of about 137 hectares (+24%). New forest grew on about 147 hectares, while 9 hectares were lost.
What is the tree count in Siwān?
Siwān has an estimated 87,965 trees across the 12.57 km² measured — 28.0% tree cover, 12 percentage points short of the 40% tree-cover target set for this area.
How many more trees does Siwān need?
Siwān needs roughly 37,699 more trees to close a 12-point shortfall against its 40% tree-cover target — about 829.4 t of extra CO₂ absorbed per year once grown.
How are Siwān's air quality and tree cover measured?
Air quality is measured by ground monitoring stations near Kagzi Muhalla, via OpenAQ; the 7-day trend is the Open-Meteo / CAMS model's estimate. Tree cover is measured from Sentinel-2 L2A (ESA Copernicus) via Earth Search satellite imagery at 10 m detail across a 2 km radius around Kagzi Muhalla; the tree count is an estimate derived from that cover.
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