Smog engulfed Delhi and neighbouring areas as the air quality fell sharply in the past two days putting health of residents in the National Capital Region at risk.
The air quality index has dramatically dropped by 60-80 points in since Saturday and is now inching towards the 'very poor' zone, when children are advised not to spend time outdoors. Weather condition too have played a role in the appearance of smog.
According to a TOI report, uncontrolled burning of paddy stubbles by Punjab farmers is the main reason behind this sharp drop in the air quality of Delhi NCR.
A satellite image from NASA's Earth Observing System Data and Information System (EOSDIS) website on Saturday showed 'fire spots', which denote blazes on the ground, all across Punjab and parts of northern Haryana. Haze can be seen enveloping a large region of northern India, including NCR.
According to another NASA website that maps fires, this season's stubble-burning in Punjab started around October 10 and reached its peak around October 30. Data for the last three days shows a sharp rise in the fires. During October and early part of November, farmers ready their fields for the sowing of the winter (rabi) crop.
Curiously, the images show the fires restricted to Punjab, except for parts of northern Haryana that border the state. Although stubble-burning is officially banned in Punjab, farmers continue to set fire to their crop residues twice a year because it's the cheapest way to get rid of the paddy stubbles.
Pollution - from the farm fires and well as other regular sources - appears to have combined with weather conditions to cause the rapid fall in air quality over Delhi. Met officials said light easterly winds over the past couple of days have brought moisture into Delhi's air. Pollutants are known to stick to moisture droplets, causing smog.
Met officials said that the wind direction is likely to change from Monday or Tuesday raising the possibility of more pollutants coming in from Punjab.