At least four people were killed on Wednesday evening as parts of Karachi were gripped by gusty winds accompanied by a dust storm that led to power outages and infrastructural damage.

Two people died while as many were injured after walls collapsed due to the strong winds in two separate incidents in Gulistan-i-Jauhar and Gulshan-i-Maymar areas, a spokesperson for the Edhi foundation said.

In Taiser Town, a 45-year-old man died after the roof of his house collapsed, while a 60-year-old woman died in a wall-collapse incident in Saadi Town Block 5, according to the Chhipa Information Bureau.

Explaining the phenomenon, Karachi weatherman Sardar Sarfaraz told Dawn that Karachi's northwestern areas and the entire east Balochistan was covered under a westerly trough, which combined with the city's hot and humid weather to produce a dust storm.

As is normally the case, the dust storm caused light rain in some areas and drizzle in others, Sarfaraz added.

"It is a short-lived phenomenon and has exited most areas," he said, adding that the weather event could cause light rain or drizzle in some areas later in the night as well.

He clarified that the dust storm was not a result of Cyclone Nisarga, which he said had passed 750 kilometres away from Karachi's coast. The cyclone also passed by Mumbai's south, he noted.

Sarfaraz further said the Met department's airport office had issued a local Met warning to aviation authorities at around 7:45pm about the dust storm's approach.

The first gust was recorded at Karachi airport at 8:05pm; it blew for quite a while at the speed of 30-35 knots (65-70km per hour), he added.

Earlier this evening, the Pakistan Meteorological Department (PMD) had issued an advisory asking fishermen of Sindh to remain careful and "not to venture in deep sea till June 4 due to rough sea conditions".

"Severe Cyclonic Storm (SCS) Nisarga moved further north-eastward with [a] speed of 20km per hour during last six hours and made landfall near south Gujarat-Maharashtra coast, India," the advisory said.

Meanwhile, a massive fire, caused by heavy winds, broke out in Surjani Town during the dust storm.

Edhi ambulances and firefighters rushed to the site to extinguish the fire after Chief Minister Murad Ali Shah instructed Commissioner Karachi Iftikhar Shallwani to exercise all possible means to bring the fire under control and minimise the loss of life.

Power outages across the megalopolis were reported soon after the dust storm struck, and were confirmed by K-Electric.

"Due to high winds and dust storm, certain areas of Karachi facing power supply interruptions. KE teams have begun working to restore power in areas where weather permits," the power utility wrote on Twitter.