Delhi air deteriorates to 'very poor' due to calm winds, average AQI at 355

After a two-day gap, Delhi's air quality turned 'very poor' again on Sunday as calm winds prevented dispersion of pollutants. Some areas in the national capital recorded 'severe' pollution levels.

Delhi's 24-hour average Air Quality Index (AQI) was recorded at 355 at 4 pm as against 255 on Saturday, Central Pollution Control Board (CPCB) data showed.

Data from 37 of the city's 40 monitoring stations was shared by the CPCB. It showed that three stations -- Bawana, Burari and Jahangirpuri -- recorded 'severe' air quality.

The air quality was also 'very poor' in Delhi's neighbouring areas like Greater Noida, Ghaziabad and Noida and 'poor' in Faridabad and Gurugram.

Under the Graded Response Action Plan (GRAP), a set of emergency measures to control air pollution in the Delhi-NCR region during winter, 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).

According to the India Meteorological Department (IMD), wind speed in the city was recorded at 0 kmph.

Favourable wind speed had improved Delhi's air quality from 'very poor' to 'poor' over the last two days.

The prominent pollutants in Delhi on Sunday were PM10 and PM2.5, according to the CPCB.

The PM2.5 level was recorded at 110.6 micrograms per cubic metre at 5 pm, the data showed.

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 13 per cent, according to the Centre's Decision Support System for Air Quality Management.

It predicted that vehicular emissions will remain the top contributor to Delhi's pollution over the next two days.

Delhi recorded a maximum temperature of 34.2 degrees Celsius, two notches above normal, according to the India Meteorological Department (IMD).

The weather department has forecast a clear sky in the city on Monday. The minimum and maximum temperatures are expected to settle around 20 degrees Celsius and 34 degrees Celsius respectively.