A third dust storm in a month, this time highly widespread but not intense, has emerged and engulfed the entire Arabian Sea in dust, according to an air quality researcher scientist on Saturday.
As seen on satellite imagery over the last two days, there has been a slow but consistent intrusion owing to favourable winds and a push due to a westerly disturbance — the same that brought hailstorm to NW India, including parts of Delhi — has marked the entry of a massive dust cloud with a low density near the Surat coast.
This has caused the Air Quality Index (AQI) in Ahmedabad and the surrounding areas, all the way up to the Maharashtra coast, to fall into the very poor category.
“The impact has been in Mumbai for two days, but the relatively less AQI of Mumbai turned from satisfactory to poor since Friday. It is predicted that the same dust cloud will further intensify with the clouds of Afghanistan and the upper edge of the Thar region of Pakistan and will further deteriorate the AQI for places along the Mumbai – Ahmedabad belt,” said Gufran Beig, founder-director of SAFAR.
It is expected to subside by Monday, owing to warmer local conditions, he said.
The Indian Institute of Tropical Meteorology (IITM), Pune, is part of the Ministry of Earth Science’s SAFAR (System of Air Quality and Weather Forecasting and Research).
According to SAFAR data, Ahmedabad’s PM10 concentration was 225 (moderate) on Saturday, while PM2.5 levels were 120. (poor).
For Mumbai, PM10 was 231, and PM2.5 was 125.
Explaining why Delhi and other parts of NW India received hailstorms and thunderstorms while Ahmedabad and Mumbai got dust storms due to the same Western Disturbance (WD), Beig said: “The wind direction is always towards Mumbai-Ahmedabad corridor whenever there is WD. It brings huge moisture in the northern part of India but nothing in southwest India, except fast upper air winds, which are otherwise slow. These high winds push dust in that area.”
Previously, in the first week of February, Mumbai had experienced extremely high pollution levels for three days in a row, with Air Quality Indexes ranging from 300 to 400 in some areas.
This was due to the worst air quality being caused by two back-to-back dust storms.