Tirunelveli — Seasonal Pollution Patterns
Month-by-month air quality patterns for Tirunelveli across 1 years of CPCB data. Based on CPCB station data, 2016–present.
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At a glance
Based on 1 years of CPCB monitoring across 1 stations, Tirunelveli averages AQI 30 annually, with a pronounced seasonal pattern classified as flat year-round. The worst month is October at AQI 36 (Good) and the cleanest is September at AQI 27 (Good) — a 9-point swing between them. Severe days (AQI > 400) make up 0% of the record while Good-or-Satisfactory days account for 100.0%.
The four seasons
Indian meteorological seasons: Winter (Dec–Feb), Summer (Mar–May), Monsoon (Jun–Sep), Post-monsoon (Oct–Nov).
Winter
AQI 29Summer
AQI 0Monsoon
AQI 28Post-monsoon
AQI 33Climograph — 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2024 | — | — | — | — | — | — | — | 30 | 27 | 36 | 29 | 29 | 30 |
| Avg | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 30 | 27 | 36 | 29 | 29 | — |
Winter in Tirunelveli
Winter (Dec–Jan–Feb) in Tirunelveli averages AQI 29 across 21 measured days — Good on the NAQI scale. 0% of those days fall in Very Poor or Severe; 100% are Good or Satisfactory. Winter in Tirunelveli is not the headline season, but shallow morning inversions can still produce short spikes. Tirunelveli's cleanest months lie elsewhere in the calendar, so the winter response is less about evacuation than about protecting sensitive groups on the worst individual days.
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 37 (Good), versus 35 (Good) for the rest of October. 6 sampled days across the CPCB record.
Stubble-burning window (Oct 15 – Nov 15)
In-window severe-day share 0% vs 0% 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 29 (Good), compared with an annual mean of 30.
Summer
Summer (Mar–Apr–May) in Tirunelveli averages AQI 0 across 0 measured days — Good on the NAQI scale. 0% of those days fall in Very Poor or Severe; 0% are Good or Satisfactory. Summer air in Tirunelveli 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. Tirunelveli's summer mean of 0 is the lighter side of the year for outdoor activity, though hot afternoons can still irritate sensitive airways.
Monsoon
Monsoon (Jun–Jul–Aug–Sep) in Tirunelveli averages AQI 28 across 45 measured days — Good on the NAQI scale. 0% of those days fall in Very Poor or Severe; 100% are Good or Satisfactory. The Jul 15 – Sep 15 core monsoon window averages AQI 29, a 3.3% improvement on the annual mean of 30. 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. For anyone with asthma or heart conditions, monsoon is the easy-breathing stretch of the year in Tirunelveli.
Post-monsoon
Post-monsoon (Oct–Nov) in Tirunelveli averages AQI 33 across 53 measured days — Good on the NAQI scale. 0% of those days fall in Very Poor or Severe; 100% are Good or Satisfactory. Post-monsoon in Tirunelveli 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 1-year CPCB record.
Daily calendar heatmap
Every measured day for the last 1 years. Expand for the full 1-year archive.
Month-by-month deep dive
Tap any month to expand.
Jan—+0%
No data for this month.
Feb—+0%
No data for this month.
Mar—+0%
No data for this month.
Apr—+0%
No data for this month.
May—+0%
No data for this month.
Jun—+0%
No data for this month.
Jul—+0%
No data for this month.
Aug2024–2024Latest AQI 30+0%
Aug in Tirunelveli averages AQI 30 (Good) in the most recent year, having moved from 30 in 2024. Direction: stable (+0.0%).
Sep2024–2024Latest AQI 27+0%
Sep in Tirunelveli averages AQI 27 (Good) in the most recent year, having moved from 27 in 2024. Direction: stable (+0.0%).
Oct2024–2024Latest AQI 36+0%
Oct in Tirunelveli averages AQI 36 (Good) in the most recent year, having moved from 36 in 2024. Direction: stable (+0.0%).
Nov2024–2024Latest AQI 29+0%
Nov in Tirunelveli averages AQI 29 (Good) in the most recent year, having moved from 29 in 2024. Direction: stable (+0.0%).
Dec2024–2024Latest AQI 29+0%
Dec in Tirunelveli averages AQI 29 (Good) in the most recent year, having moved from 29 in 2024. Direction: stable (+0.0%).
Cities with similar (and opposite) seasonal profiles
Ranked by cosine similarity of 12-month AQI signatures across monitored Indian cities.
What to do with this information
If you are choosing when to visit Tirunelveli 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 October in Tirunelveli 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 Tirunelveli?
October is the most polluted month in Tirunelveli on average, with a long-run AQI of 36 — firmly in the Good band. This is drawn from 1 CPCB monitoring stations across 1 years of daily readings. Through October, 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 Tirunelveli?
September is the cleanest month of the year in Tirunelveli, averaging AQI 27 in the Good band. The months immediately before and after also tend to sit well below the annual mean of 30, 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 Tirunelveli's air spike in October?
Tirunelveli's profile is relatively flat year-round; the small October reflects modest swings in wind, rainfall and local emissions rather than a dramatic seasonal mechanism.
How bad is Diwali air quality in Tirunelveli?
Across the CPCB record, the week around Diwali in Tirunelveli averages AQI 37 — 1.07× the normal October baseline of AQI 35, a spike of 3 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 Tirunelveli's air?
Only partially. Tirunelveli's monsoon window averages AQI 29, which is a 3.3% change from the annual mean of 30. Rain does scrub particulates, but the improvement here is modest — pointing to persistent local sources (industry, traffic, dust) that rain cannot fully wash away.
Is Tirunelveli's worst season getting worse or better year-on-year?
We need more years of CPCB coverage in Tirunelveli to quantify year-on-year change with confidence.
Which months are safest to visit Tirunelveli?
September is the single best month at AQI 27. Based on the 12-month averages, the three cleanest months in Tirunelveli are September (AQI 27), November (AQI 29), December (AQI 29). 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 October, when the baseline jumps into Good territory.
How does Tirunelveli's seasonal pattern compare to Delhi?
Tirunelveli is classified as flat year-round, while Delhi is strongly winter-dominant with a large Diwali and stubble-burning signal. If the two look similar, interventions that work in Delhi (BS-VI vehicle rollout, construction-dust control, seasonal industry curtailment) are worth trialling here. If they look very different, the dominant sources in Tirunelveli are likely different and the policy mix should reflect that.