Air in Delhi and NCR becomes toxic before Diwali: AQI exceeds 400 in several areas, GRAP-3 proves ineffective

Even after the introduction of Stage-2 of the Graded Response Action Plan (GRAP), the air quality in Delhi has not improved. According to data from the Central Pollution Control Board (CPCB), the overall Air Quality Index (AQI) in Delhi was 331, which falls into the 'very poor' category. The most critical situation was recorded in Jahangirpuri, where the AQI reached 449.

Furthermore, in areas such as Rohini, Alipur, Punjabi Bagh, and Vivek Vihar, the AQI exceeded the 400 mark and was classified as 'hazardous'.

Data was also presented for other areas: in Noida, Sector 62 recorded an AQI of 404 on Tuesday, placing it in the 'hazardous' category. In Sector 39, the AQI was 365, in Sector 150 it was 343, and in Sector 116 it was 272.

Under Stage-2 of GRAP, government bodies will intensify control measures to combat pollution. Daily street cleaning will be carried out using mechanical and vacuum sweepers. Dust suppressants will be sprayed along with water to prevent dust.

Special campaigns will be organized in areas that are pollution hotspots, and supervision over compliance with dust control rules at construction sites will be strengthened. Parking fees will be increased to reduce the use of private transport. Residents are advised to use public transport or work from home if their job allows. Established restrictions on the use of coal and wood are also being applied.

The air in the capital city of Delhi has become extremely polluted this season. On Monday morning, a thick haze hung over the city, and pollution levels sharply increased. Although previous rains provided some relief, the air once again turned toxic.

According to data from the Central Pollution Control Board (CPCB), at 7:05 AM on Monday, the Air Quality Index (AQI) reached 349, which falls into the 'very poor' category. The average daily AQI on Sunday was 261 (poor), while the day before that it was 117 (moderate). On Friday after the rain, the AQI dropped to 60, marking the cleanest day in October in four years, but the situation worsened again.

Ninety-eight percent of the available data was collected from 58 out of 59 air quality monitoring stations in Delhi. At 36 of these stations, the air was in the 'very poor' category. The Jahangirpuri station was the only one where the AQI reached 417 and entered the 'hazardous' category. Five stations showed a 'moderate' level, and the rest were classified as 'poor.'

In the morning, PM2.5 was the main pollutant at most stations. PM2.5 was the primary source of pollution at 51 of the 58 stations, and PM10 at the remaining seven. CPCB defines air quality as follows: 0-50 — good, 51-100 — satisfactory, 101-200 — moderate, 201-300 — poor, 301-400 — very poor, and 401-500 — hazardous.

According to NASA satellite observations, 1394 instances of field burning were detected in Punjab and Haryana between November 1 and November 1: 1249 in Punjab and 145 in Haryana. Only 171 fires were registered on November 1. Last year, 1861 fires were detected during a similar period. However, this data does not reflect the full picture, as most straw is now burned in the evening. In 2025, about 98 percent of fires occurred after 3:00 PM, compared to 94 percent in 2024. Since the satellite passes around 1:30 PM, evening fires often go unnoticed. These burnings are one of the main external factors affecting the air in Delhi.

The rise in AQI is due to a combination of several scientific reasons. Firstly, there are local pollution sources: vehicle exhaust, factories, construction work, and road dust release pollutants daily. Rain washed away these substances, but as soon as the rain stopped, these sources became active again. Secondly, a significant factor is the smog from straw burning in Punjab and Haryana, which is carried by the wind into Delhi-NCR. Thirdly, and this is a very important factor, are adverse weather conditions. Meteorologist Navdeep Dahiya noted that the wind is blowing from the northwest and has a very low speed, meaning it is calm. With calm winds, pollutants do not disperse and remain in the air for a long time. During winter, temperature inversion is often observed, where the air near the ground remains cold, and a warm layer forms above it. This layer prevents pollutants from rising, causing them to accumulate near the ground surface. PM2.5 particles are very small and can penetrate the lungs, coming from transport, burning, and industry. When the wind is still, these particles easily accumulate, and the AQI rises quickly. With the approach of Diwali, the use of fireworks and burning may intensify pollution.

Meteorologist Navdeep Dahiya warned that the smog season has begun. Most sensors in Delhi-NCR show an AQI above 300, and at night in many places, it approaches 400-500. With calm winds from the northwest, all emissions will remain in the atmosphere for a long time. Favorable weather conditions are not expected for the next seven to ten days, which means a possible further intensification of smog. This year, Delhi last recorded 'very poor' air quality on February 11, when the average AQI was 305; before that, on February 4, it reached 339. The worsening situation in early November is causing concern.

The government is implementing measures to combat smog and is carrying out pollution control measures. Fines amounting to millions of rupees have been imposed in a single day, and many vehicles have been impounded. However, long-term relief is only possible with a reduction in field fires, decreased transport emissions, and favorable weather conditions. Citizens are advised to spend less time outdoors in the morning and evening, use masks, and pay special attention to children and the elderly. Home air purifiers can help. The air in Delhi reached the 'very poor' category for the first time this season. After the relief from the rains, pollution took over again. Straw burning, local emissions, and adverse weather jointly increase the AQI. From a scientific point of view, calm wind and temperature keep pollutants near the ground. The situation may worsen in the coming days. Only caution and collective efforts can bring relief.