Dense fog covered the metropolis early on Monday morning, resulting in poor visibility and triggering flight delays.
The visibility was reduced to 100-150 metres at Karachi Airport, the Met Office said, affecting departure and arrival of flights.
PIA flight PK-732 arriving from Jeddah was re-routed to Nawabshah, a flight inquiry official informed. A Turkish Airlines flight coming to Karachi from Istanbul was directed to Dubai. PIA flight PK-214 was re-routed to Muscat.
A flight arriving here from Faisalabad was delayed due to the fog, while a Qatar Airways flight arriving from Qatar was also delayed.
Traffic flow across the city was also disrupted by the thick blanket of fog, resulting in traffic jams.