Rajasthan is a large, unusually diverse state in western India. It has a long frontier with Pakistan, and from north to south touches the adjacent states of Punjab, Haryana, Uttar Pradesh, Madhya Pradesh, and Gujarat. Rajasthan adds to its own internal, social, economic, and political complexity some of the features of each of these disparate neighbors. The dominant geological feature in Rajasthan is the Aravalli range, which runs south to north through the heart of the state. This barrier almost completely arrests the already faltering summer monsoon, creating a semiarid and desert zone to the west and a more watered region in the east.