Haleji Lake was a saline lagoon until the 1930s and was converted into a reservoir to provide additional water to Karachi.[2]
During World War II, additional water was required for troops stationed at Karachi. The then-British Government of Sindh Province decided to increase the capacity of the lake by introducing a feeder canal from the Indus River. Salt water was drained out and an embankment was constructed around the lake which was fed with fresh water through a canal. The work was placed on a war footing and was completed within 24 months in 1943.