AQI: The air quality in Delhi remained in the "very poor" category on Saturday, with an Air Quality Index (AQI) of 321, according to the latest available data. The day before, the AQI in the national capital was recorded at 359. Several areas in Delhi experienced firecracker bursting, including Lajpat Nagar, Kalkaji, Chhatarpur, Jaunapur, East of Kailash, Saket, Rohini, Dwarka, Punjabi Bagh, Vikas Puri, Dilshad Garden, and Burari.
Following Diwali on October 31, the Air Quality Index (AQI) in Delhi on Friday was recorded to be approximately 14 times higher than the limit recommended by the World Health Organization (WHO). The concentration of PM2.5, a major pollutant, in Delhi at 8 a.m. was measured at 209.3 micrograms per cubic meter according to data from the Central Pollution Control Board (CPCB). The WHO guidelines specify a permissible limit of 15 micrograms per cubic meter over a 24-hour period.
Better than before
However, the Delhi Pollution Control Committee reported a 4% decrease in PM2.5 levels, a hazardous particulate matter, during this year's Diwali compared to the previous year. Conversely, PM10 levels, representing particulate matter measuring 10 micrometres or smaller, experienced an 11% increase.
According to data from the Central Pollution Control Board (CPCB), Delhi experienced its most polluted Diwali in the past three years. The city's 24-hour average Air Quality Index (AQI) on Thursday was measured at 330, surpassing the levels recorded in 2023 (218) and 2022 (312).
The report also noted that the majority of air quality monitoring stations in Delhi reported consistently high pollution levels, with 37 out of 39 stations indicating "very poor" air quality.
The average air quality over a 24-hour period on pre-Diwali and Diwali days this year was poorer compared to the last two years. However, on the day after Diwali, the pollution levels did not worsen as much as in previous years, thanks to a significant increase in wind speed in the morning hours on Friday.
On Friday, the post-Diwali 24-hour average Air Quality Index (AQI) was 339, which is an improvement from last year's AQI of 358 on November 13, 2023. This positive change can be attributed to various factors, with meteorological conditions playing a crucial role. The wind speed reached 10kmph around 9 am, creating favorable conditions for the dispersion of pollutants.
The Air Quality Index (AQI) was introduced in 2014 by the central government as a part of the Swachh Bharat campaign to enhance the public's understanding of pollution. An expert group consisting of medical professionals, air quality experts, academia, advocacy groups, and other stakeholders was formed to oversee the development of the AQI. The technical study was commissioned by IIT Kanpur, who along with the Expert Group, proposed an AQI scheme.
As per the Central Pollution Control Board, the Air Quality Index (AQI) simplifies intricate air quality data from multiple pollutants into a singular numerical value, name, and corresponding color. Pollutants monitored include PM 10, PM 2.5, Nitrogen Dioxide, Ozone, Carbon, and more.
The AQI is categorised as follows:
0 to 50: "good" 51 to 100: "satisfactory" 101 to 200: "moderate" 201 to 300: "poor" 301 to 400: "very poor" 401 to 500: "severe"