Fires in Punjab, Pakistan's fields could worsen Delhi's air quality due to smoke drift

The air in Delhi has once again become toxic shortly before the celebration of Diwali. In the capital, the Air Quality Index (AQI) has been in the poor to very poor range for the fourth consecutive day. In the morning, dense smog and haze were observed in many areas. The deterioration of the situation is linked to weather changes, low wind speed, emissions from transport, and instances of stubble burning in Punjab.

The level of pollution in Delhi began to rise before winter; in areas such as Akshardham, a thick veil of smog was visible in the morning. The AQI in Delhi reached about 230–250, and at some monitoring stations, the air quality reached the 'very poor' category. According to the Central Pollution Control Board (CPCB) standards, an AQI from 201 to 300 is classified as 'poor,' and from 301 to 400 as 'very poor.' This means that even in the 'poor' category, the air can be harmful to health, especially for children, the elderly, and individuals with heart or respiratory diseases.

According to meteorological department forecasts, current weather conditions and wind speed may hinder the dispersion of pollutants, so the possibility of a quick improvement depends on the weather conditions.

A significant factor contributing to the rise in pollution in Delhi is vehicle exhaust fumes. A large number of private cars, diesel buses, and other commercial vehicles operate in the capital. Furthermore, the air quality is worsened by dust from construction work, road dust, and the practice of burning waste.

To control pollution, it is necessary not only to reduce the number of vehicles but also to effectively implement measures such as checking Pollution Under Control Certificates (PUCC), preventing dust on construction sites, and banning open waste burning.

Winds blowing from the northwest also affect the air quality in Delhi. The increase in stubble burning after rice harvesting in Punjab and Haryana can aggravate the pollution problem. To stop stubble burning, state governments must provide farmers with access to machinery and alternative methods to eliminate the need to burn crop residues in the fields.

However, the entire responsibility for Delhi's pollution cannot be placed solely on stubble; numerous factors influence the air quality, including transport, construction activities, road dust, and weather conditions.

To combat pollution in Delhi-NCR, the Commission for Air Quality Management (CAQM) has established phased measures under the Graded Response Action Plan (GRAP). On October 21, 2026, an order was issued to implement the first phase of GRAP measures due to the worsening air quality in Delhi-NCR. The first phase of GRAP is activated when the AQI reaches the 'poor' level (from 201 to 300). Measures taken under this phase include mechanical cleaning of roads, water sprinkling, dust control at construction sites, and a ban on open waste burning. Municipal bodies and relevant agencies are obligated to monitor the implementation of these measures to curb dust and local pollution sources.

In September 2026, CAQM approved a revised GRAP program that includes certain measures related to controlling polluting vehicles in the first phase. These include entry restrictions into NCR and neighboring states for buses meeting BS-IV standards and older.

Particles generated from road dust and construction work play an important role in increasing pollution. According to GRAP, mechanical road cleaning, water sprinkling, and dust prevention measures at construction sites must be carried out. Part of these measures also includes a ban on open waste burning and regular waste collection.

The effect of these rules will only be noticeable with regular inspection of construction sites and action against violators. Coordination between Delhi, Punjab, Haryana, and other NCR states is required to reduce transport emissions, control construction dust, regularly clean streets, and decrease stubble burning incidents.

If wind speed remains low and effective control over pollution sources is not implemented, the situation may worsen in the coming days. Therefore, it is crucial to monitor how strictly governments enforce the directives issued under GRAP and how long the residents of Delhi can breathe clean air.

Following the Dasara festival, pollution levels in the Delhi-NCR region significantly increased, reaching hazardous levels. The Air Quality Index (AQI) surpassed the mark of 300 due to smoke from fireworks and stubble burning.

To stabilize the situation, GRAP 1 restrictions were implemented, which prohibit construction work and open waste burning. According to meteorological service forecasts, the situation may worsen in the coming days.

Even before the celebration of Diwali, Delhi experienced extremely heavy smog as air quality deteriorates earlier than usual. According to data from the Central Pollution Control Board (CPCB), on the night of October 21, when most city residents were asleep, 45 out of 53 monitoring stations recorded poor or worse air pollution.

According to CPCB readings, at 1 AM, the average PM2.5 level in Delhi was 191.2 micrograms per cubic meter, which falls into the 'very poor' category on the CPCB scale. This period, which began on October 14, was the most polluted of the week.

Under the national air quality standard set by CPCB in 2009, the established limit for the daily average PM2.5 in India is 60 micrograms per cubic meter.

However, when considering the overall Air Quality Index (AQI), the situation in October this year was slightly better compared to last year. The daily CPCB bulletin showed that on October 20, the AQI in Delhi was 179, corresponding to the 'moderate' category. The average AQI for the period from October 1 to October 20 reached 154.6, whereas in 2025, it was 178.7 for the same period. During this period, the AQI never reached the 'poor' or 'severe' category.

However, looking at hourly data paints a more alarming picture. Analysis of CPCB data by Aaj Tak revealed that during the last week, 24.9% of the 59 registered PM2.5 sensors were in poor or severe condition before 1 AM. The daily average does not reflect information about the dirtiest hours, which often occur during people's sleep, night shifts, or early morning work.

Analysis of hourly data for the week demonstrates that pollution levels increase at night. According to India Today, about two-thirds of the readings recorded in the 'very poor' and 'hazardous' categories occurred between 9:00 PM and 6:00 AM.

In the middle of the day, on October 15, when wind speed was higher, pollution levels significantly decreased. According to CPCB, at 2:00 PM, the wind speed was 2.3 meters per second, and the average PM2.5 level in the city dropped to 9 micrograms per cubic meter, marking the cleanest hour of the week.

The air in Delhi continues to become more polluted. An analysis by India Today shows that during the first week of October, the average PM2.5 content in the air was 59.3 micrograms per cubic meter. By October 20, this figure rose to 71.2 micrograms, representing an increase in pollution of approximately 20%.

According to CPCB, from October 1 until now, the average PM2.5 level in Delhi at 12:00 AM was the highest—80.4 micrograms per cubic meter, and at 3:00 PM, it was the lowest—44.4 micrograms. In the period from 12:00 AM to 6:00 AM, the PM2.5 concentration in the air was 1.6 times higher than in the period from 12:00 PM to 6:00 PM.

According to CPCB, around 12:00 AM, the average wind speed at Delhi stations was 0.6 meters per second, while at 3:00 PM, it increased to 1 meter per second. It was observed that pollution was higher during hours of low wind speed. However, based solely on this correlation, one cannot conclude that low wind speed is the cause of the rising pollution.

Every year, farmers from Punjab, Haryana, and Uttar Pradesh burn rice straw in October. The Indian Agricultural Research Institute (IARI) tracks these incidents using satellite imagery. According to IARI, from October 1 to October 20, 506 instances of straw burning were recorded in these three states: 345 in Punjab, 155 in Uttar Pradesh, and 6 in Haryana. Between 2018 and 2024, the number of such incidents on these dates fluctuated between 2031 and 9722. Last year, 817 cases were recorded for this period.

Despite the air being more polluted in Delhi this month, the number of straw burning incidents in the three neighboring states remains low. Typically, most straw burning occurs in the second half of October. According to IARI, between 2018 and 2024, 83.6% to 94.5% of all straw burning incidents in these three states were registered after October 20, meaning most incidents of this season are yet to come.

The rise in air pollution in Delhi is caused not only by smoke from field straw burning. A study conducted by The Energy and Resources Institute (TERI) and the Automotive Research Association of India (ARAI) assessed various sources of PM2.5 pollution in Delhi during the winter season of 2016-2017. According to this study, vehicle exhaust contributed 23%, while crop residue burning and domestic burning accounted for 22%. Road and construction dust made up 15%, and industrial units accounted for 10%. Furthermore, 26% of the pollution was caused by the formation of particles from other gases in the atmosphere.