Temperature dropped and air cleared in Delhi-NCR; AQI below 100 in many areas

When comparing the air quality in four major cities in the country, the air in Delhi was the most polluted on Tuesday. According to data from the Central Pollution Control Board (CPCB), the Air Quality Index (AQI) in Delhi was 197. In Chennai, this figure reached 143, in Mumbai it was 99, and in Kolkata it was 81. Thus, Delhi ranked first among all four cities, while Kolkata ranked last.

The AQI is a scale that determines the degree of air purity or pollution in a city; the higher the value, the more polluted the air is considered. This is why on October 27, the air in Delhi appeared the most polluted among all four cities.

The specific figures for the four cities were as follows: Delhi — 197, Chennai — 143, Mumbai — 99, and Kolkata — 81. The AQI in Kolkata was the lowest.

Comparing the data for Delhi and Chennai, it is evident that the AQI in Delhi (197) exceeds the figure in Chennai (143) by 54 points. This gap widens even further compared to the figures for Mumbai (99) and Kolkata (81), indicating that the air in Delhi is more polluted than in the other three cities.

In the CPCB graph, AQI levels are divided into different categories. According to this scale, AQI values from 101 to 200 fall into the 'moderate' category. Based on this, the readings for Delhi (197) and Chennai (143) fell into the moderate category. Meanwhile, the figures for Mumbai (99) and Kolkata (81) were below 100, meaning they did not reach the lower boundary of the moderate category.

It is important to note that the CPCB data is based on the 24-hour average value calculated as of around 4:00 PM on Tuesday.

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.