The Cholistan desert was a fertile and well populated area when the Hakara river flowed through it around 4000 and 1000 BC. When the river and its tributaries changed course and dried up 600 years ago, the settlements began to disappear and the people of the area were forced, by an unbearably harsh environment, to migrate to more favourable places to lead their nomadic life. The old bed of the Hakara river still shows the remains of a series of decayed forts (Akbar et. al., 1996; FAO, 1993).