Before India's Independence in 1947, the major evidence for pre-Iron Age farming-based societies consisted of the Indus or Harappan Civilization, almost all of whose sites were located in the Indus valley and Baluchistan (now Pakistan). Within the Indian borders the only evidence of such societies consisted of surface finds of ground stone tools from south, east and northeast India and the Kashmir valley. Since Independence one of the major concerns of Indian archaeologists has been to trace the diffusion of farming-based settled life in the country. As a result of sustained explorations over a 1000 sites of the Harappan civilization have been discovered in Gujarat, north Rajasthan, Punjab, Haryana and western Uttar Pradesh, and a number of them have been excavated. Besides, a large number of Neolithic and Chalcolithic sites have been located, and some of them excavated, mainly in the semi-arid region of western India and the Deccan, but some also in the Kashmir valley, the Ganga plains, northeast India and the Eastern Ghats. As a result of this work, several Chalcolithic cultures have been identified in Mewar (eastern Rajasthan), Malwa (western Madhya Pradesh) and the northern Deccan (western Maharashtra). Similarly, three distinct Neolithic cultures have been identified — one each in south India, Kashmir valley, and eastern and northeastern India.