The deserts in Pakistan and India fall in the category of the Monsoon Deserts. “Monsoon,” derived from an Arabic word for “season,” refers to a wind system with pronounced seasonal reversal. Monsoons develop in response to temperature variations between continents and oceans. The southeast trade winds of the Indian Ocean, for example, provide heavy summer rains in India as they move onshore. As the monsoon crosses India, it loses moisture on the eastern slopes of the Aravalli Range. The Rajasthan Desert of India and the Thar Desert of Pakistan are parts of a monsoon desert region west of the range.
The Thar Desert: The origin of the Thar desert is a controversial subject. Some consider it to be only 4000 to 10,000 years old, whereas others state that aridity started in this region much earlier. Also known as The Great Indian Desert, the huge unending expanse of burning hot sand is spread over four states in India, namely Punjab, Haryana, Rajasthan, and Gujarat, and two states in Pakistan and covers an area of about 446,000 square kilometers. Deriving its name from ‘thul‘ denoting the sand ridges of the region. Presently the portion of Thar Desert in Pakistan falls in the Sindh province and sharing the rest of it with Rajasthan in India. The Thar Desert, however, is not an inhospitable, empty wasteland, but is often called, with good reason, the `Friendly Desert’. It is accessible, not too hot, and colorful and makes a perfect four-day trip from Karachi. More than half a million people, 70 percent of whom are Hindu, live in the desert, spread out over 13,000 square kilometers (5,000 square miles). The women wear long, full, red or orange skirts and cover their heads with embroidered or tie-dyed shawls. Married women encase their arms in bone or plastic bangles from wrist to shoulder (widows wear bangles above the elbows only; single girls wear them only round the wrist). The people live in round mud-walled huts thatched with grass and surrounded with thick thorn hedges. These are clustered round the more reliable wells or along the tops of ridges.
The Cholistan Desert: The fascinating barren landscapes of the Cholistan (locally known as Rohi) starts some 30 kilometers from Bahawalpur and is spread over an area of some 16,000 square kilometers and extends up to the Thar desert in the Sindh province. The word Cholistan is derived from ‘Cholna’ which means moving. The people of Cholistan lead a semi-nomadic life, moving from one place to another in search of water and fodder for their animals. Drawar Fort is the major landmark of Cholistan Desert, located 48 kilometers from Dera Nawab Sahib (once headquarters and the seat of the rulers of Bahawalpur state). The area was once well watered by the river Ghaggar now called the Hakra in Pakistan and known in Vedic times as the Sarasvati. All along the 500-km of dried up river are over 400 archaeological sites, which date back to the Indus civilization 4500 years ago and are clustered around Drawar Fort. The desert has an average rainfall of 5 inches a year and there is very little cultivation.