Delhi air quality ‘severe’, likely to improve from tomorrow

The national capital on Wednesday woke up to a dense smog as the air quality was recorded in ‘severe’ category. Major pollutants PM 2.5 -- fine particulate matter in the air with a diameter of less than 2.5 micrometre, and PM 10 --- particulate matter 10 micrometer or less in diameter, were recorded at 475 and 594, respectively in the Wazirpur area, while AQI in the Anand Vihar area was at 291 and 232 respectively. Delhi’s air quality had dipped significantly since Sunday and the authorities had warned that it would deteriorate further in the next few days because of the fall in temperature that leads to the slower dispersion of pollutants.

“As per inputs received from IMD, wind direction will change from Thursday. At present, easterly winds, which are weak and bring moisture, were blowing, trapping pollutants. It is likely to change to north-westerly, which are strong and cold winds that help in the disbursal of pollutants,” Hindustan Times quoted a senior official as saying.

On Tuesday, the chairperson of the Supreme Court-appointed Environment Pollution Control Authority, Bhure Lal, said stringent actions would be taken if "severe" conditions persisted for another 48 hours. The actions include emergency measures like rationing of vehicles on roads and a ban on construction activities.

However, things could turn for the better if a sufficient amount of rainfall occurs as predicted by the Meteorological Department of India. It can be expected that the air quality will hover around the ‘poor’ category. "Levels of gaseous pollutants, NOx and CO are forecast to be enhanced -- up to moderate range -- after a long time due to a fall in boundary layer height and reduced vertical mixing," according to SAFAR.

Delhi is reeling under the menace of air pollution for the past couple of years. The region faced a major air quality crisis last year when severe pollution level forced the shutdown of schools and colleges. In 2016, the government tried to explore the possibility of cloud seeding for artificial rain but the plan never worked out. 

AQI categories:

1. An AQI between 0 and 50 is considered ‘good’
2. AQI between 51 and 100 is ‘satisfactory’
3. AQI between 101 and 200 is ‘moderate’
4. AQI between 201 and 300 is ‘poor’
5. AQI between 301 and 400 is ‘very poor’