Saharsa — Seasonal Pollution Patterns
Month-by-month air quality patterns for Saharsa across 4 years of CPCB data. Based on CPCB station data, 2016–present.
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At a glance
Based on 4 years of CPCB monitoring across 1 stations, Saharsa averages AQI 188 annually, with a pronounced seasonal pattern classified as monsoon-cleansed. The worst month is January at AQI 322 (Very Poor) and the cleanest is September at AQI 75 (Satisfactory) — a 247-point swing between them. Severe days (AQI > 400) make up 1.4% of the record while Good-or-Satisfactory days account for 28.4%.
The four seasons
Indian meteorological seasons: Winter (Dec–Feb), Summer (Mar–May), Monsoon (Jun–Sep), Post-monsoon (Oct–Nov).
Winter
AQI 291Summer
AQI 171Monsoon
AQI 102Post-monsoon
AQI 185Climograph — monthly averages and Poor+ days
Bars show the long-run AQI average per month. The overlay line counts days in Poor, Very Poor or Severe bands.
Year × month heatmap
One cell per year-month combination.
Each cell = monthly average AQI for that year-month combination. Row averages on the right, column averages at the bottom.
| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Avg |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2021 | — | — | — | — | — | — | — | — | — | — | 354 | 272 | 278 |
| 2022 | 278 | 292 | 282 | 200 | 150 | 175 | 123 | 144 | 117 | 144 | 317 | 365 | 227 |
| 2023 | 362 | 312 | 227 | 195 | 148 | 155 | 94 | 107 | 88 | 98 | 243 | 311 | 197 |
| 2024 | 335 | 198 | 111 | 136 | 87 | 72 | 70 | 58 | 56 | 81 | 218 | 208 | 139 |
| Avg | 322 | 269 | 205 | 177 | 126 | 131 | 95 | 104 | 75 | 107 | 258 | 285 | — |
Winter in Saharsa
Winter (Dec–Jan–Feb) in Saharsa averages AQI 291 across 262 measured days — Poor on the NAQI scale. 48.9% of those days fall in Very Poor or Severe; 1.5% are Good or Satisfactory. Year-on-year, winter improved by 23.1% in the most recent comparison. Winter is the defining season for Saharsa's air quality. Shallow temperature inversions trap local vehicle, industrial and biomass emissions near ground level, while regional transport patterns bring in dust and biomass smoke from upwind regions. Cool, stagnant mornings compound the problem; visibility falls, respiratory complaints spike, and short-term pollution peaks of AQI 400+ are routine. Sensitive groups — children, elderly, asthma and cardiac patients — should treat the full Dec–Jan–Feb window as a mandatory mask-and-purifier period.
Diwali, stubble burning and the monsoon
Three India-specific signatures that shape the seasonal curve.
Diwali week impact
The 7-day window around Diwali averages AQI 202 (Poor), versus 99 (Satisfactory) for the rest of October. 18 sampled days across the CPCB record.
Stubble-burning window (Oct 15 – Nov 15)
In-window severe-day share 0% vs 1.6% outside the window. The difference is a direct signal of upwind crop-residue transport.
Monsoon cleansing (Jul 15 – Sep 15)
Core monsoon window averages AQI 92 (Satisfactory), compared with an annual mean of 188.
Summer
Summer (Mar–Apr–May) in Saharsa averages AQI 171 across 234 measured days — Moderate on the NAQI scale. 6.4% of those days fall in Very Poor or Severe; 18.4% are Good or Satisfactory. Year-on-year, summer improved by 41.4% in the most recent comparison. Summer air in Saharsa is shaped by a very different mix of forces. Rising temperatures drive deeper vertical mixing which dilutes local emissions, but pre-monsoon dust storms, wildfires and heat-accelerated ozone formation can all push AQI higher on individual days. Saharsa's summer mean of 171 sits in the Moderate-to-Poor range, indicating that dust and gaseous precursors dominate the seasonal profile rather than the winter particulate peak common to north Indian cities.
Monsoon
Monsoon (Jun–Jul–Aug–Sep) in Saharsa averages AQI 102 across 265 measured days — Moderate on the NAQI scale. 3.4% of those days fall in Very Poor or Severe; 65.7% are Good or Satisfactory. Year-on-year, monsoon improved by 41.5% in the most recent comparison. The Jul 15 – Sep 15 core monsoon window averages AQI 92, a 51.1% improvement on the annual mean of 188. Rain scrubs particulates out by wet deposition, and the deeper monsoon boundary layer disperses what remains vertically. Short-lived rebounds can happen between spells of rain, but the overall pattern is strongly favourable for outdoor activity. Even in monsoon, Saharsa's baseline sits in the Moderate band, pointing to persistent year-round sources that rain alone cannot rinse away.
Post-monsoon
Post-monsoon (Oct–Nov) in Saharsa averages AQI 185 across 153 measured days — Moderate on the NAQI scale. 20.3% of those days fall in Very Poor or Severe; 25.5% are Good or Satisfactory. Year-on-year, post-monsoon improved by 19.7% in the most recent comparison. Diwali and the three days either side of it average AQI 202 — 2.03× the normal October baseline of AQI 99 for Saharsa, a spike of 102 points. Post-monsoon in Saharsa is the handoff from clean monsoon air to the winter peak, and the transition is rarely gentle.
Month-by-month trajectories
How each month has moved across the 4-year CPCB record.
First year vs latest year
Annual and per-season comparison.
Across the 4-year CPCB record Saharsa is improving overall — AQI moved from 278 in 2021 to 139 in 2024, a -50% change. No month shows a material worsening of 10% or more. Months that improved most: Nov (-38.4%), Dec (-23.5%). Because Saharsa's seasonal shape is monsoon-cleansed, policy action that targets the January peak buys disproportionate relief — most city-wide annual averages are dragged upwards by the worst two or three months.
Daily calendar heatmap
Every measured day for the last 3 years. Expand for the full 4-year archive.
Month-by-month deep dive
Tap any month to expand.
Jan2022–2024Latest AQI 335+21%
Jan in Saharsa averages AQI 335 (Very Poor) in the most recent year, having moved from 278 in 2022. Direction: worsening (+20.5%).
Feb2022–2024Latest AQI 198-32%
Feb in Saharsa averages AQI 198 (Moderate) in the most recent year, having moved from 292 in 2022. Direction: improving (-32.2%).
Mar2022–2024Latest AQI 111-61%
Mar in Saharsa averages AQI 111 (Moderate) in the most recent year, having moved from 282 in 2022. Direction: improving (-60.6%).
Apr2022–2024Latest AQI 136-32%
Apr in Saharsa averages AQI 136 (Moderate) in the most recent year, having moved from 200 in 2022. Direction: improving (-32.0%).
May2022–2024Latest AQI 87-42%
May in Saharsa averages AQI 87 (Satisfactory) in the most recent year, having moved from 150 in 2022. Direction: improving (-42.0%).
Jun2022–2024Latest AQI 72-59%
Jun in Saharsa averages AQI 72 (Satisfactory) in the most recent year, having moved from 175 in 2022. Direction: improving (-58.9%).
Jul2022–2024Latest AQI 70-43%
Jul in Saharsa averages AQI 70 (Satisfactory) in the most recent year, having moved from 123 in 2022. Direction: improving (-43.1%).
Aug2022–2024Latest AQI 58-60%
Aug in Saharsa averages AQI 58 (Satisfactory) in the most recent year, having moved from 144 in 2022. Direction: improving (-59.7%).
Sep2022–2024Latest AQI 56-52%
Sep in Saharsa averages AQI 56 (Satisfactory) in the most recent year, having moved from 117 in 2022. Direction: improving (-52.1%).
Oct2022–2024Latest AQI 81-44%
Oct in Saharsa averages AQI 81 (Satisfactory) in the most recent year, having moved from 144 in 2022. Direction: improving (-43.7%).
Nov2021–2024Latest AQI 218-38%
Nov in Saharsa averages AQI 218 (Poor) in the most recent year, having moved from 354 in 2021. Direction: improving (-38.4%).
Dec2021–2024Latest AQI 208-24%
Dec in Saharsa averages AQI 208 (Poor) in the most recent year, having moved from 272 in 2021. Direction: improving (-23.5%).
Cities with similar (and opposite) seasonal profiles
Ranked by cosine similarity of 12-month AQI signatures across monitored Indian cities.
Similar seasonal profile
Cities whose 12-month AQI signature most closely matches Saharsa.
Opposite seasonal profile
Cities whose seasonal signature least resembles Saharsa.
What to do with this information
If you are choosing when to visit Saharsa or plan outdoor events — marathons, weddings, school sports, outdoor festivals — the CPCB record says September and the two adjacent months are the lowest-risk window. Daily variability still matters; check the live AQI page before committing on any specific date. Sensitive groups should treat January in Saharsa as an indoor-air-priority month: close windows on high-AQI evenings, run a purifier with a HEPA filter rated for your room size, and reserve outdoor exercise for clear-weather mornings. On days above AQI 300, even healthy adults benefit from well-fitted N95 or KN95 masks for outdoor commutes.
Frequently asked questions
Which is the most polluted month in Saharsa?
January is the most polluted month in Saharsa on average, with a long-run AQI of 322 — firmly in the Very Poor band. This is drawn from 1 CPCB monitoring stations across 4 years of daily readings. Through January, residents should expect elevated PM2.5 and PM10, reduced visibility on cooler mornings, and strong recommendations from doctors to limit outdoor exertion, wear well-fitted N95 masks, and run indoor purifiers through evening and overnight hours when pollutant accumulation typically peaks.
What is the cleanest month to visit Saharsa?
September is the cleanest month of the year in Saharsa, averaging AQI 75 in the Satisfactory band. The months immediately before and after also tend to sit well below the annual mean of 188, so a visit window centred on September is the safest choice for outdoor sightseeing, marathons, school trips and wedding events. Mornings are usually the crispest time to head out; pollution tends to creep up slightly during the evening commute even in the cleanest months. Always cross-check the day-of live AQI before any high-exertion outdoor plan.
Why does Saharsa's air spike in January?
Saharsa shows a clear monsoon-cleansed signature — rain and deeper atmospheric mixing drop AQI to a seasonal trough, and everything else relative to that trough looks elevated. The specific January spike combines pre-monsoon dust, post-rain rebounds and the arrival of cool-season trapping effects.
How bad is Diwali air quality in Saharsa?
Across the CPCB record, the week around Diwali in Saharsa averages AQI 202 — 2.03× the normal October baseline of AQI 99, a spike of 102 AQI points. Firework particulates combine with a cooler, more stagnant late-October atmosphere to produce some of the worst air-quality days of the entire year. Sensitive groups should treat Diwali eve and the two days after as peak-alert days: stay indoors, close windows by evening, run purifiers on high, and reserve any outdoor celebrations for daytime hours when mixing is strongest.
Does the monsoon actually clean Saharsa's air?
Yes — meaningfully. Saharsa's core monsoon window (Jul 15 – Sep 15) averages AQI 92, a 51.1% improvement on the annual mean of 188. Rain removes airborne particulates by wet deposition, and the deeper monsoon boundary layer disperses what remains vertically. Across 265 measured monsoon days we see 65.7% in the Good-or-Satisfactory band.
Is Saharsa's worst season getting worse or better year-on-year?
Between 2021 and 2024, Saharsa's annual average AQI moved from 278 to 139 — a change of -50%. In the most recent year-on-year comparison, the winter season specifically improved by 23.1%. The long-run direction is improving — NCAP policy pressure, cleaner fuels and tighter vehicle standards are showing up.
Which months are safest to visit Saharsa?
September is the single best month at AQI 75. Based on the 12-month averages, the three cleanest months in Saharsa are September (AQI 75), July (AQI 95), August (AQI 104). These are the safest choices for outdoor itineraries, long walks, open-air concerts and day-trips. Sensitive groups can treat these months as near-normal activity windows but should still check live AQI for the specific date. Avoid planning outdoor-heavy trips in January, when the baseline jumps into Very Poor territory.
How does Saharsa's seasonal pattern compare to other Indian cities?
Saharsa is classified as monsoon-cleansed. Based on a 12-month cosine-similarity index computed across all monitored Indian cities, the city whose seasonal signature most closely resembles Saharsa's is Bhagalpur (Bihar), with its own worst month in January. Cities with similar signatures often respond to similar policy levers — if a neighbouring peer has demonstrated improvements through specific interventions (construction-dust controls, bus electrification, brick-kiln regulation), they are likely candidates for Saharsa too. The peer-city panel on this page lists the closest four additional matches.