Delhi's air quality remained in the very poor' category on Monday, owing to a drop in wind speed, which has hindered the dispersion of pollutants across the city, experts said.
The city's 24-hour average Air Quality Index (AQI) was recorded at 304 at 4 pm, down from 355 on Sunday, according to data from the Central Pollution Control Board (CPCB).
Data from 36 of the city's 40 monitoring stations showed 23 stations, including Bawana, Burari, Jahangirpuri, Dwarka, Rohini, Anand Vihar, Mundka, Patparganj, Sonia Vihar, Wazirpur, Ashok Vihar, Aya Nagar, Mandir Marg, Okhla, Najafgarh, and Nehru Nagar, were in the very poor' category.
Delhi's neighbouring Ghaziabad, Faridabad, Greater Noida, and Noida, fared slightly better with their air quality in the poor' category.
In contrast, Gurugram's air quality was moderate' with a reading of 187, according to data from the CPCB.
Air quality is categorised into four stages Stage I -- "Poor" (AQI 201-300), Stage II -- "Very Poor" (AQI 301-400), Stage III -- "Severe" (AQI 401-450), and Stage IV -- "Severe Plus" (AQI above 450).
"Delhi's AQI rose from 270 on October 25 to 356 on October 27. The increase was due to a change in wind direction and speed," Abhishek Kar, Senior Programme Lead at the Council on Energy, Environment, and Water (CEEW), said.
On October 25, the average wind speed of the city was 2.4 m/s, coming from the east and southeast.
By Sunday, the wind direction shifted to the northwest, and the average wind speed dropped to 0.8 m/s. Winds from the northwest bring pollutants from stubble burning towards Delhi, Kar said.
The city's AQI is forecasted to be between 350 and 400 on Diwali.
"CAQM should consider implementing Stage 3 or 4 of the GRAP preemptively based on these forecasts. Moreover, authorities should strictly enforce the firecracker ban to prevent further deterioration of air quality during Diwali," he said.
Prominent pollutants clogging the city air on Monday were PM10 and PM2.5, according to the CPCB.
The PM2.5 level was recorded at 121 micrograms per cubic metre at 5 pm, whereas PM 10 was 239.5 according to the data.
PM2.5 is fine particulate matter capable of penetrating deep into the respiratory system and triggering health problems.
PM10 is particulate matter that is 10 micrometres or less in diameter. These tiny solid or liquid particles suspended in the air can be inhaled deep into the lungs, potentially leading to issues such as asthma, bronchitis, and other respiratory diseases.
Vehicular emission was the biggest contributor to Delhi's pollution on Sunday, accounting for approximately 10.7 per cent, according to the Centre's Decision Support System for Air Quality Management.
It is predicted that vehicular emissions will remain the top contributor to Delhi's pollution over the next two days, with an estimated share of approximately 14 per cent.
Apart from transport, other prominent contributors to Delhi's pollution include farm fires.
Data shows that on Sunday, a total of 138 farm fires were recorded in Punjab, 13 in Haryana, and 27 in Uttar Pradesh.
Between September 15, 2024, and October 27, 2024, a total of 1,995, 713, 892, and four farm fires were recorded in Punjab, Haryana, Uttar Pradesh, and Delhi.
The Delhi government on Monday announced plans to deploy 10,000 civil defence volunteers, who were terminated from service last year as bus marshals, to help the government implement pollution mitigation measures.
The volunteers will be deployed alongside teams from the Municipal Corporation of Delhi , the Delhi Pollution Control Committee, and the Transport Department, Chief Minister Atishi said.
Delhi registered a maximum temperature of 34.4 degrees Celsius on Monday, 3.4 degrees above normal, according to the weather department.
The temperature was between 30 and 31 degrees Celsius around the same period last year.
The weather department has forecast a clear sky in the city on Tuesday.
The minimum and maximum temperatures are expected to settle around 20 degrees Celsius and 34 degrees Celsius respectively.
