12 Dec 2018
Delhi's air-quality remains 'severe', mild rain adds to pollution woes
The Central Pollution Control Board (CPCB) recorded an overall air quality index (AQI) of 413.
The AQI on Monday has been recorded at 412 and on Tuesday it was at 415.
Rohini, Wazirpur, Ashok Vihar edged towards 'severe plus emergency' category
Ghaziabad and Noida also recorded severe air quality. Ghaziabad's air quality was the worst at an AQI of 429, the CPCB data showed.
Faridabad recorded very poor air quality, it said.
29 areas in Delhi recorded severe air quality and in eight areas it was recorded at very poor.
Rohini, Bawana, Ashok Vihar, and Wazirpur edged towards severe plus emergency category, said CPCB.
Insufficient rain led to deterioration of air quality: SAFAR
The overall PM2.5 level (fine particulate matter in the air with a diameter less than 2.5 micrometers) was recorded at 257 and the PM10 level at 423, the CPCB said.
The Center-run System of Air Quality and Weather Forecasting (SAFAR) said meteorological conditions leading to insufficient rain led to the deterioration of the air quality.
Moist air is forming fog over Delhi, said SAFAR.
Air quality likely to remain 'severe' for next two days
"There is a fall in temperature and a good amount of moisture is present in the air. Moist air is passing over Delhi's cool surface leading to fog formation and calm winds are not allowing pollutants to disperse," the SAFAR said.
According to the Indian Meteorological Department (IMD), the air quality is likely to remain under the severe category for the next two days.
Humidity level was recorded at 98% today: MeT
The situation is likely to improve when wind speed picks up, said IMD
The relative humidity was recorded today at 98%, MeT officials said.
"Levels of gaseous pollutants, NOx and CO, are forecast to be enhanced, up to the moderate range, after a long time due to a fall in boundary layer height and reduced vertical mixing," it said.
Ventilation index highly unfavorable for dispersion of pollutants: IITM
According to the Indian Institute of Tropical Meteorology (IITM), the maximum ventilation index is likely to be 3,500 sqm/second from December 10-12.
The ventilation index lower than 6,000 sqm/second with average wind speed less than 10 kmph is unfavorable for dispersion of pollutants.
The wind speed, ventilation index, and higher moisture are highly unfavorable for dispersion of pollutants, the IITM added.
Different categories of Air Quality Index (AQI)
An AQI between 201 and 300 is considered poor, 301 and 400 very poor and 401 and 500 severe. According to experts, even healthy people find it hard to breathe when air quality level is at severe and doctors advise minimum physical activity.
- Air Pollution
- Pollution in Delhi
- Air Quality Index
- Ashok Vihar
- Center-run System
- Central Pollution Control Board
- Indian Institute
- Indian Institute of Tropical Meteorology
- Indian Meteorological Department
- Tropical Meteorology
- Weather Forecasting