Desert similar. They occur in regions where large temperature differences occur between sea and land. Moist warm air rises over the land, deposits its water content and circulates back to sea. Further inland, areas receive very little precipitation. The Thar Desert near the India/Pakistan border is of this type. In some parts of the world, deserts are created by a rain shadow effect. Orographic lift occurs as air masses rise to pass over high ground. In the process they cool and lose much of their moisture by precipitation on the windward slope of the mountain range. When they descend on the
Thar Desert or man-made (johads), are often the only source of water for animals and humans in the true desert areas. The lack of a constant water supply causes much of the local population to live as nomads. Most human settlements are found near the two seasonal streams of the Karon-Jhar hills. Potable groundwater is also rare in the Thar desert. Supplies are often sour due to dissolved minerals, and are only available deep underground. Wells that successfully bear sweet water attract nearby settlement, but are difficult to dig, possibly claiming the lives of the well-diggers. According to 1980 housing census in