Delhi’s Air Quality Remains ‘Poor’, Likely To Turn ‘Very Poor’ By Sunday
Delhi’s air quality remained "poor" and is likely to slip into the "very poor" category by Sunday, officials said.
On Friday, Delhi’s Air Quality Index had a reading of 208, which falls in "poor" category. The city experienced poor air quality for the first time this season on Thursday, the Centre-run System of Air Quality and Weather Forecasting And Research said.
The Central Pollution Control Board recorded Delhi's air quality in the "poor" category on Friday, with an AQI of 216 and PM10—particulate matter 10 micrometres or less in diameter—and PM2.5 as the prominent pollutants.
Particles narrower than 10 micrometres are the most hazardous because they can get deep into the lungs, and some may even get into the bloodstream. The city's AQI is predicted to slip to 239 on Saturday.
According to SAFAR, crop stubble burning has increased significantly in Punjab and Haryana over the last two days and will now start influencing Delhi's AQI. The national capital's AQI may start deteriorating from Oct. 13, "towards very poor", it said.
"Late monsoon withdrawal is not good for the air quality in north India. During the third and fourth week of October, the temperature will also start to cool. The anticyclone, which persists as part of the withdrawal, along with clear skies and sinking motion, will make the atmosphere very stable beneath...means significantly calm surface winds," SAFAR said.
These factors will lead to stagnant weather conditions—low wind speed, descending air, and compressed boundary layer—which favour rapid fine particulate matter formation and accumulation of pollutants. The situation becomes bad if any additional internal (like firecrackers) or external (stubble burning) sources contribute to it.
Mahesh Palawat of private weather forecaster Skymet Weather Services Pvt. Ltd., said the situation is likely to deteriorate rapidly on Oct. 20-22 when the wind will change direction from easterly to northwesterly and westerly.
Westerly and northwesterly winds bring dust from western regions and smoke caused by crop stubble burning in Punjab and Haryana to Delhi NCR.
Starting Oct. 15, stricter measures to fight air pollution came into force in New Delhi and the National Capital Region as part of the Graded Response Action Plan, which was first implemented in Delhi NCR in 2017.
These measures included increasing bus and metro services, hiking parking fees and stopping use of diesel generator sets when the air quality turns poor. When situation turns "severe", GRAP recommends closure of brick kilns, stone crushers and hot mix plants, sprinkling of water, frequent mechanised cleaning of roads and maximising power generation from natural gas.
The measures to be followed in the "emergency" situation include stopping entry of trucks in Delhi and construction activities, and introduction of the odd-even car rationing scheme.