Stubble Burning Season Indoor Air India

When the Season Runs

Paddy residue burning across Punjab and Haryana usually begins in early
October, once the rice harvest comes in, and continues through November.
The concentrated period — the largest number of fires — typically falls in late October and
early November.

That timing is not incidental. It overlaps precisely with the point when temperatures drop
and the atmosphere stops mixing vertically, so the smoke that would disperse in September sits
near the ground instead.

Why It Happens

Worth understanding properly, because the coverage is often more heated than informative.

Farmers in Punjab and Haryana harvest rice and then need to sow wheat. The window between
the two is narrow — a matter of weeks. Rice leaves behind a large volume of tough residue that
has to be cleared before sowing.

Burning clears a field in hours and costs nothing. The alternatives — residue-management
machinery, or equipment that sows directly through the residue — cost money and time. For a
smallholder on a thin margin with a short window, the economics are not subtle.

None of that makes the smoke less harmful. But it explains why the practice persists through
successive bans, and why the solutions that work are agricultural and economic rather than
simply prohibitive.

How Much It Actually Contributes

This is where public discussion tends to lose accuracy in both directions — either stubble
burning is blamed for everything, or dismissed as a distraction from local sources.

The honest answer is that the contribution varies enormously from day to day.
On many days during the season it is a modest share of Delhi’s particulate load. On peak days,
when a large number of fires coincides with wind blowing from the northwest toward the capital,
it becomes a very large share and drives the worst air of the year.

Both things are true, and the variability is the real finding: local sources — vehicles,
construction, industry, waste burning — form the persistent baseline, and stubble burning
supplies the spikes on top of it.

Who It Reaches

Delhi-NCR gets the coverage, but the smoke does not respect the boundary. Depending on wind,
the affected belt extends across large parts of Punjab, Haryana, Uttar Pradesh, Rajasthan and
into Bihar. Cities well outside the news cycle experience severe days too.

If you are in the northern plains, this season affects you whether or not your city is
mentioned on television.

Preparing Before It Starts

Everything on this list is cheaper and easier in September.

• Seal window frames and door bottoms. Weather-stripping is the highest
  return per rupee available, and stock disappears from hardware shops once the season is in the
  news.
• Replace filters now. A purifier entering peak season with a saturated
  filter will not deliver. Buy a spare while they are available.
• Service the kitchen chimney. Your own cooking is a significant indoor
  source, and a grease-clogged baffle barely extracts.
• Decide which room is the clean room. Usually the bedroom — the easiest to
  keep closed and where you spend the most continuous hours.
• Stock fitted N95s. Not cloth, not surgical.

Getting Through the Peak

Condition	What changes
Moderate day	Normal routine. Ventilate in the afternoon, briefly
Poor to very poor	Skip outdoor exercise. Keep windows shut. Run filtration in occupied rooms
Severe (400+)	Stay in. No ventilation window. No indoor combustion — incense, candles, smoking. Extractor on for every meal. Fitted N95 if you must go out

One point worth repeating because it is consistently misunderstood: filtration works on a
closed room. During this season, an air purifier running with the window open
is filtering Punjab.

Frequently Asked Questions

When does stubble burning season start in India?

Paddy residue burning in Punjab and Haryana typically begins in early October, once the rice harvest is in, and runs through November. The sharpest few weeks are usually late October into early November, when the largest number of fires overlaps with falling temperatures that trap smoke near the ground.

How much does stubble burning contribute to Delhi’s pollution?

It varies enormously day to day — from a small single-digit share on many days to a very large share on peak days when wind direction carries smoke directly toward the capital. That variability is the point: stubble burning is not a constant background contributor but an episodic one that produces the worst individual days of the year.

Why do farmers burn stubble?

The window between harvesting rice and sowing wheat is short, and burning is the fastest and cheapest way to clear residue from the field. Mechanical alternatives exist but cost money and time that many smallholders do not have. It is an economic problem before it is an environmental one.

Does an air purifier help during stubble burning season?

Indoors, in a closed and correctly sized room, yes — stubble smoke is fine particulate, which is exactly what HEPA filtration captures. It does nothing for outdoor exposure, and it cannot keep up with an open window. Sealing gaps matters at least as much as the appliance.

Is stubble burning smoke worse than normal city pollution?

It is not chemically unique, but it arrives as a large additional load of fine particulate on top of an already high baseline, and it arrives in the weeks when cold still air is least able to disperse it. That combination — not the smoke alone — is what produces the severe days.