Port city ranks worst on global Air Quality Index
Mazar-i-Quaid is enveloped in haze as smog-like conditions prevailed in the city on Saturday. Photo: Online
Karachi ranked the worst on a global Air Quality Index on Wednesday morning, placing atop the world’s most polluted cities. It was closely followed by Lahore. Earlier this month, Karachi featured third on the list, with only Lahore and India’s Delhi preceding it.
The AQI in the port city was recorded at 331 yesterday (Wednesday) morning while Lahore’s AQI was recorded at 280.
An AQI as high as 151-200 is considered unhealthy while an AQI between 201 to 300 is more harmful and an AQI over 300 is dubbed extremely hazardous.
Around 11am, Karachi’s air was still harmful with its AQI at 221. The port city had, however, fallen down on the list - ranking fourth by this time yesterday. Lahore ranked third with an AQI of 227, Delhi ranked second and Bulgaria’s capital city, Sofia, rose to first by then.
According to experts, the air is heavier in the winter as compared to summer, causing poisonous particles in the atmosphere to move downwards and making the atmosphere polluted. As a result, a layer of polluted particles, including large amounts of carbon and smoke, covers the city.
The smoke produced by factories and by burning coal, garbage, oil or tyres enters the atmosphere and the effects of this appear at the onset of winter and remain till the season’s end, say experts.
Thus, air pollution reaches extremely dangerous levels, severely compromising air quality.
Although southwestern winds blowing from the sea may work as a filter for the air, these winds remain mostly suspended during winter, according to experts.
They noted that winds blowing from the northeast increased the concentration of hidden polluted particles, and a healthy atmosphere in such a situation is subject to rainfall, which washes off all polluted particles.
Published in The Express Tribune, December 3rd, 2020.