Desert greening desiccating winds and the invasion of sand. The Rajasthan Canal system in India is the major irrigation scheme of the Thar Desert and is intended to reclaim it and to check spreading of the desert to fertile areas. Prevention of shifting sand dunes is accomplished through plantations of "Acacia tortilis" near Laxmangarh town. There are few local tree species suitable for planting in the desert region and these are slow growing. The introduction of exotic tree species in the desert for plantation has become necessary. Many species of Eucalyptus, Acacia, Cassia and other genera from Israel, Australia, US, Russia, Zimbabwe,
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