Delhi’s air quality in ‘poor’ category, mercury likely to plunge to 5 degrees

AQI between zero and 50 is considered “good”, 51 and 100 “satisfactory”, 101 and 200 “moderate”, 201 and 300 “poor”, 301 and 400 “very poor”, and 401 and 500 “severe”

NEW DELHI: Delhi’s air quality was in the “poor” category on Thursday morning while the mercury was likely to plunge to five degrees Celsius while the maximum temperature was expected to be 17 degrees Celsius.

A cold winter morning in New Delhi. (ANI)

According to the Central Pollution Control Board, the hourly Air Quality Index (AQI) was 263 at 7 am. On Wednesday, the average 24-hour AQI was 186 in the “moderate” category.

An AQI between zero and 50 is considered “good”, 51 and 100 “satisfactory”, 101 and 200 “moderate”, 201 and 300 “poor”, 301 and 400 “very poor”, and 401 and 500 “severe”.

On Thursday, the System of Air Quality and Weather Forecasting And Research said the foggy conditions and low temperatures, as well as low mixing layer height, were preventing efficient ventilation of pollutants leading to AQI being within the “poor” category” for the two days. “From 29th [Saturday] onwards, AQI is likely to improve due to gradual increase of day temperature enhancing vertical mixing and dilution of near-surface pollutants.”

The minimum temperature on Wednesday was 5.8 degrees Celsius, three notches below normal, and the maximum 16.4 degrees Celsius, six degrees below normal.