Environment and Disaster Management › Pollution

Air pollution

The National Clean Air Programme and the sources of polluted air, from vehicles and power plants to crop burning, dust and indoor fuel. Prelims has asked which gases are used to calculate the Air Quality Index and about the World Health Organization (WHO) air quality guidelines.

Foundation notes: The Graded Response Action Plan · Air quality: the standards and the index

Showing 3 of 7 articles, those that changed from 1 to 30 September 2026.Show all

National Clean Air Programme

Prelims and Mains

The National Clean Air Programme (NCAP), launched in 2019, sets 130 cities, most of them non-attainment cities, a target for one pollutant and pays them to meet it.

It aims to cut PM10 by up to 40 per cent by 2025–26, measured against 2017–18.
Cities are paid through performance linked grants, tracked on the Portal for Regulation of Air Pollution in Non-Attainment cities (PRANA).
Of the money spent by 2026, 68 per cent went on road dust, and little on transport, waste or industry.
By 2026, 40 cities had not finished source apportionment.

What changed

7 Sep 2026
- Against 2017 to 2018, 108 of the 130 cities had lower annual PM10, 26 cut it by more than 40 per cent and 14 met the standards.
- Of the grants given since 2019 to 2020, 70.5 per cent has been used.
- The Swachh Vayu Survekshan rankings reward effort over results: measured PM10 improvement carries only 2.5 per cent of the weightage.
- Lucknow thus topped the largest cities although its PM10 is more than twice the standard.
Mains: ring fenced funds with penalties for non use, targets aimed at combustion rather than dust, and payments to farmers to diversify crops.
PIB, 7 Sep 2026: India's Path to Blue Skies: From Awareness to Action for Cleaner Air (opens in a new tab) · The Indian Express, 7 Sep 2026: Lucknow's air cleanest, Indore among top 3 in Centre's annual survey (opens in a new tab)

Stubble burning and crop residue management

Prelims and Mains

Stubble burning is the burning of paddy residue in the fields of Punjab, Haryana and Uttar Pradesh after harvest, in October and November.

Two routes for stubble

In the field

Incorporated into the soil by machines from custom hiring centres

Outside the field

Biomass power
Compressed biogas
Ethanol
Pellets
Co firing in thermal plants

Burning ends only when straw has somewhere to go, either back into the soil or into a market.Source: PIB, 16 June 2026

How much it adds, and how it is counted

It is a modest share of the season's particulate pollution and a large share of it on the worst days.
Farm fires add no more than 15 per cent of winter particulate pollution, but more than a third on some October and November days.
How the fires are counted decides how the argument runs.
Fire counts see active fires during daytime satellite passes, and miss fires lit after the satellites have gone.
Burnt area maps scorched fields from Sentinel 2 images, and says nothing about how much smoke a fire released.

Why farmers burn, and the alternatives

Burning is driven by the short gap between paddy harvest and wheat sowing, which short duration paddy and direct seeded rice widen.
The Crop Residue Management scheme of 2018 funds machines and custom hiring centres in Punjab, Haryana, Uttar Pradesh and Madhya Pradesh.
Residue can go back into the soil or into a market, as biomass power, compressed biogas, ethanol, pellets or co firing in thermal plants.

What changed

4 Sep 2026
- CAQM opened talks with Punjab and the Indian Space Research Organisation (ISRO) on how stubble burning is counted, doubting that fire counts capture it.
- Peak burning moved from about 1.30 pm in 2020 to about 5 pm in 2024, after the satellites have passed.
- Fire counts in Punjab and Haryana fell 93 and 91 per cent from 2021 to 2025, but burnt area fell far more slowly.
- The burnt area protocol is being re-tested as satellite and ground data diverge.
The Hindu, 4 Sep 2026: Air quality panel holding talks with Punjab govt. and ISRO over tracking of stubble fires (opens in a new tab) · The Indian Express, 7 Sep 2026: Air quality management body to re-test burnt area protocol as satellite, ground data diverge (opens in a new tab)

GRAP and Delhi's winter plan, 2026

Prelims and Mains

LeadDelhi's winter air: the revised GRAP and a fixed calendar of curbsSeptember 2026

Why in news

On 28 September 2026 CAQM approved a revised GRAP schedule, and Delhi announced a winter plan with curbs fixed by date from 1 November 2026 to 31 January 2027.

Background

GRAP has four stages tied to the Air Quality Index: Stage I at 201 to 300 (poor), Stage II at 301 to 400 (very poor), Stage III at 401 to 450 (severe) and Stage IV above 450 (severe plus).
Each stage adds to the one below, and a stage can be invoked on a forecast, before the reading crosses its band.
In winter, falling temperatures trap vehicle exhaust, industrial emissions and crop residue smoke close to the ground.

What changed in GRAP

Curbs on diesel generator sets and on the entry of buses of BS IV and below moved up from Stage II to Stage I.
The exemption for goods vehicles of BS IV and below carrying essential commodities in Stages III and IV was removed.
Dust monitoring of construction sites was extended beyond municipal limits to industrial and highway corridor zones.

Delhi's fixed calendar

From 1 November to 31 January dust generating construction stops, parking charges double, offices stagger their hours and up to half the staff work from home.
All construction and demolition is banned from 10 December to 20 January.
From 1 November vehicles below BS VI registered outside Delhi are barred, with compressed natural gas and electric vehicles exempt.
From 1 October a vehicle without a valid Pollution Under Control Certificate gets no fuel in the region.

The farm fire side

CAQM has directed Punjab, Haryana and Uttar Pradesh to eliminate paddy stubble burning in 2026.
A strong El Niño is expected to bring fewer rain bearing Western Disturbances, so the air will clear less often this winter.

GRAP stages, as revised in September 2026

Stage	Air Quality Index	Air quality	Actions
I	201 to 300	poor	25
II	301 to 400	very poor	8
III	401 to 450	severe	10
IV	above 450	severe plus	5

The curbs tighten from Stage I to Stage IV, and each stage adds to the ones below.Source: PIB, 29 September 2026

The way forward

A fixed calendar gives residents and businesses notice, which graded curbs never did, but it treats the season and not the sources.
Vehicles are the largest primary source of Delhi's winter pollution, at about 23 per cent, so cleaner transport matters more than seasonal bans.
Municipal and even regional boundaries are too small for the problem, which is the case for managing the whole airshed.

Prelims facts

GRAP stages follow the Air Quality Index: 201, 301, 401 and above 450.
CAQM is a statutory body and acts through directions that the States must enforce.
The airshed approach manages air quality across a shared geographic area and not within administrative boundaries.
BS VI norms, in force nationwide since 2020, set stricter limits on nitrogen oxides and particulate matter.

Open the lead on its own page

The Graded Response Action Plan (GRAP) is the set of emergency curbs for Delhi and the National Capital Region that switch on in four stages as the Air Quality Index worsens.

It is run by the Commission for Air Quality Management (CAQM), a statutory body under an Act of 2021.
Its curbs arrive only when the air has already turned bad, so Delhi has added a winter plan that fixes restrictions by calendar date.

What changed

29 Sep 2026LeadDelhi's winter air: the revised GRAP and a fixed calendar of curbs