Reduced wind speed, dense fog and low temperature pushed the air quality in Delhi into ‘severe’ category on Friday. The overall air quality index (AQI) in Delhi was 432 on Friday.
At 7.30pm, the air quality at several monitoring stations had already dropped to the emergency zone. The AQI at Okhla phase 2, Mundka, Pusa, Vivek Vihar, Ashok Vihar, Nehru Nagar and Jawaharlal Nehru Stadium monitoring stations had crossed the 450 mark.
The particulate matter levels also showed an upward curve throughout Friday. At 1am on Friday, the PM 2.5 (particulate matter with diameter less than 2.5 micrcometres) levels was recorded 233ug/m3.
By 8pm, the levels were 273ug/m3, just a few points away from the emergency mark of 300ug/m3. The PM 10 (particulate matter with diameter less than 10 micrometres) also shot up to 402ug/m3. The emergency mark for PM 10 levels are 500ug/m3.
Scientists at the India Meteorological Department (IMD) said that from Thursday evening the winds have remained calm and the dense fog spells in the morning and night are making the situation worse.
A senior scientist at the IMD said that the forecast is possibility of light rain from late Friday night and Saturday, which will bring some relief for the pollution levels.