Winter is coming. Can NCR pass the pollution test?

Across nine NCR locations studied, October's air was better on average than a year ago. But last winter's fine-particle pollution shows how much remains at stake.

It is that time of year again. Daily AQI readings are back in the headlines, masks are coming out, and the familiar argument over who is responsible for the smog has begun. Across the NCR, festive lights often have to compete with the haze that settles over the region.

This year, the start wasn't great.

The first week of October 2026 was considerably more polluted than the same week in 2025. TOI compared the Central Pollution Control Board's (CPCB) daily Air Quality Index (AQI) bulletins for October 1-24 across nine NCR locations with complete readings in both years. In the first seven days, their average AQI rose from 110 to 173.

Over the full 24 days, however, the picture changed. The average fell from 185.2 last year to 161.6 this year. Across those nine locations, daily readings classified as Poor or worse, meaning an AQI above 200, dropped from 94 to 56 out of 216 readings each year.

The improvement was widespread. Of 15 NCR locations with readings on at least 22 matching dates in both years, 13 recorded lower average AQI on those dates this year.

The lower October readings offer some relief. But a better AQI for a few weeks does not erase what people breathe through the rest of the year.

For a child waiting for a school bus, a traffic police officer at a busy junction or a street vendor spending the day beside traffic, exposure continues well beyond the afternoon AQI bulletin.

The largest PM2.5 particles are roughly one-thirtieth the width of a human hair.

They can reach deep into the lungs, and some particles can enter the bloodstream. Long-term exposure increases the risk of heart disease, stroke, respiratory illness and lung cancer. Children, older people and those already ill are particularly vulnerable.

Last winter showed how persistent that exposure can be. An analysis of CPCB monitoring data by the Centre for Research on Energy and Clean Air (CREA) found that between October 2025 and February 2026, Delhi exceeded India's daily PM2.5 limit of 60 µg/m³ on 144 of 151 days. That left just seven days at or below the limit. Noida breached it on 145 days. Several other NCR locations recorded almost as many breaches.

The health risk is already shaping decisions about children's activities. In September, the Commission for Air Quality Management (CAQM) advised Delhi and neighbouring NCR states to avoid holding physical sports competitions during November and December.

The University of Chicago's Air Quality Life Index (AQLI) puts the longer-term cost into years. Using 2023 exposure levels, it estimates how much average life expectancy could increase if PM2.5 were permanently reduced to the World Health Organization's annual guideline.

Nor is the health burden confined to the NCR. AQLI estimates potential gains of 5.4 years in Bihar, 5.3 years in Haryana and 5.0 years in Uttar Pradesh. The problem stretches across much of the Indo-Gangetic Plain, the densely populated belt from Punjab to West Bengal.

Delhi's average PM2.5 concentration for January to September 2026, measured through September 28, was 69 µg/m³, unchanged from the corresponding period in 2025, according to CAQM..

Bad-air episodes often affect several north Indian cities at once.

Between October 1 and 24 last year, five or more of these locations recorded Poor-or-worse air simultaneously on 11 days. This year, that happened on five days.

Delhi's AQI reached 245 on October 21, prompting CAQM to invoke Stage I of the Graded Response Action Plan (GRAP) across the NCR. The episode showed how a relatively better October can still contain days when poor air spreads across state borders.

During the monsoon, rain removes some pollutants from the air. Stronger winds can disperse emissions through a deeper layer of the atmosphere.

Winter brings colder nights, weaker winds and a shallower layer in which pollutants can mix. Sometimes warmer air sits above colder air near the ground, trapping pollution below it like a lid. This is known as a temperature inversion.

Seasonal burning and smoke transported from outside the NCR add to pollution already generated by vehicles, industries, construction and waste burning. As a result, restrictions imposed in one city cannot, by themselves, control everything residents breathe.

A July 30, 2026 environment ministry reply to Rajya Sabha, citing CAQM's expert assessment, identified several contributors to Delhi's winter PM2.5. Some pollution is emitted directly. The largest estimated share, though, forms in the air itself when gases from vehicles, factories and burning react.

Crop-residue fires remain an important part of the autumn debate. Punjab's satellite fire detections fell sharply over the full 2025 harvest season compared with 2024, although the count through October 24 is slightly higher this year than last.

Pollution also travels into the NCR from outside. On October 9, CAQM formed a 15-member expert subcommittee to identify pollution-generating areas in adjoining parts of Haryana, Punjab, Rajasthan and Uttar Pradesh. It has two months to report.

Authorities have tightened controls ahead of winter. CAQM revised its GRAP schedule in September. Following an extension of the original deadline, a tougher limit of 50 mg/Nm³ on particulate emissions from covered industrial units across the NCR took effect on October 1.

Delhi has also announced restrictions affecting commuters, offices and construction sites.

The separate no-PUCC, no-fuel rule, which bars fuel sales to vehicles without a valid Pollution Under Control Certificate, came into effect across the NCR on October 1. Delhi has also announced intensified fuel-station checks under its winter plan.

More than 10 lakh vehicles below BS-VI, the emissions standard mandatory for new vehicles since April 2020, are registered in NCR areas of Delhi, according to transport department estimates reported by TOI.

Enforcement is harder to judge. Between September 25 and October 9, CAQM reported 55 violations during 124 targeted inspections of industrial units, construction sites and diesel-generator installations.

Rs 2.6 crorein penalties

In Noida, an RTI reply obtained by environmentalist Amit Gupta showed that the Uttar Pradesh Pollution Control Board's regional office had imposed Rs 2.6 crore in penalties on more than 100 violators during 2026 through October. The board had no records showing the recovery status of the fines, TOI reported. How much has been collected remains unclear.

Rs 16,423.55 crorefunding provided to 130 cities

Rs 11,575.54 crorecities reported using

India has also spent heavily on longer-term clean-air measures. The environment ministry's September 2026 update put funding provided to 130 cities under the National Clean Air Programme (NCAP) and linked grants at Rs 16,423.55 crore for 2019-20 to 2025-26. Cities reported using Rs 11,575.54 crore, about 70.5%.

An earlier CREA audit found that most of the expenditure it reviewed went to road-dust management.

What has that achieved? NCAP measures progress against PM10, which includes coarser particles such as dust as well as finer ones. The government says PM10 levels declined in 108 of 130 programme cities in 2025-26 compared with the 2017-18 baseline. In 26 cities the reduction exceeded 40%, but only 14 met India's annual PM10 standard. CREA's earlier review, using continuous-monitor data from 100 cities, found 23 had achieved a 40% reduction. The samples and periods differ, but both show most cities falling short of a 40% cut.

Emergency restrictions are difficult to judge as well. CREA examined 12 selected escalations to Stage III or IV, GRAP's two strictest levels, three in each of four winters. In ten, AQI was higher in the week after escalation than in the preceding week. That does not show the curbs caused the increase: GRAP is triggered as pollution deteriorates.

A modelling study by the Indian Institute of Tropical Meteorology (IITM) and CAQM estimated Delhi might have experienced 60% more hours of Severe AQI without the restrictions. The curbs may therefore limit how bad the air gets even though they begin when conditions are worsening.

Delhi inaugurated 13 additional continuous air-quality monitors on October 13, and the Ministry of Earth Sciences opened a new pollution-analysis laboratory on October 24 to support more detailed forecasts and source estimates. Better data can show where to act, but cleaner air still depends on cutting emissions.