A year later, dust storms expected again
On January 23, 2022, the air quality index (AQI) shot up to 502 in the ‘severe+’ category. It is the highest-ever reading in recorded history, as per the System of Air Quality Forecasting and Research (SAFAR).
Mumbai: Exactly after one year, the city may again witness a severe dust storm leaving it engulfed in a thick blanket of dust between January 22 to January 25, under the influence of a western disturbance (WD). On January 23, 2022, the air quality index (AQI) shot up to 502 in the ‘severe+’ category. It is the highest-ever reading in recorded history, as per the System of Air Quality Forecasting and Research (SAFAR).
The corresponding 24-hour average AQI, according to the Central Pollution Control Board, was 381 (‘very poor’).
Mumbai has previously seen particularly severe dust storms in 2016, and earlier in 2012, pointed out Gufran Beig, project director, SAFAR.
WDs are storms that form in the Middle East and travel eastward, bringing sporadic and sudden winter rain to the northern parts of India, with their influence sometimes extending along the western coast and in central India. This leads to an incursion of dust from the Middle East, Pakistan and parts of Rajasthan into the Mumbai Metropolitan Region (MMR) on the backs of westerly winds. Such weather systems are typically preceded by warmer temperatures, and may even bring unseasonal rains to the city.
KS Hosalikar, head of the India Meteorological Department’s (IMD) surface instrument division, said on Thursday, “Two western disturbances are expected to sweep over north India in quick succession. One of them is currently near Pakistan right now, and its effects are being felt in Delhi, where there is some respite from the cold wave today. In Maharashtra, too, minimum temperatures are rising across the state and all observatories have seen minimum temperature at 10 degrees Celsius or more this morning. There’s a chance of dusty, hazy weather in Mumbai around January 22-24, when the second WD passes.”
The first western disturbance of the new year passed over the northwest of India between January 12 and 13, causing dust-raising winds over Iran and Pakistan. It was followed by a rapid deterioration in air quality in Mumbai, where the AQI plunged from a ‘moderate’ 134 on January 13, to a ‘poor’ 240 within a single day.
“Last year’s January 22 to 23 event was a prominent one for sure. You could see the dust in satellite images. But the one earlier this month doesn’t seem to be that prominent,” said Akshay Deoras, a research scientist at the National Centre for Atmospheric Science, University of Reading, UK. “The WD is currently approaching Pakistan and the arid regions from where the dust blows. The volume of dust needs to be in a large quantity to reach Mumbai and cause a significant deterioration of the air quality. It would be good to wait for a day or two to see how much dust is being blown. Parts of Gujarat, near the Pakistan border, would be first impacted and then depending on how much dust is there, Mumbai-MMR and northwest Maharashtra may feel the effects,” he added.
Such events over the Middle East are generally more frequent during the spring and summer seasons when factors such as high temperature, atmospheric instability, strong northwesterly winds and thunderstorms create ideal conditions for the triggering of dust storms. Dust storms observed in June and July are not able to impact Mumbai due to the mitigating influence of the monsoon.