<P> Aridification of this region during the 3rd millennium BCE may have been the initial spur for the urbanisation associated with the civilisation, but eventually also reduced the water supply enough to cause the civilisation's demise, and to scatter its population eastward . </P> <P> At its peak, the Indus Civilisation may have had a population of over five million . Inhabitants of the ancient Indus River valley developed new techniques in handicraft (carnelian products, seal carving) and metallurgy (copper, bronze, lead, and tin). The Indus cities are noted for their urban planning, baked brick houses, elaborate drainage systems, water supply systems, and clusters of large non-residential buildings . Children's toys were found in the cities, with few weapons of war, suggesting peace and prosperity . Their trade seals, decorated with animals and mythical beings, indicate they conducted thriving trade with lands as far away as Sumer in southern Mesopotamia . </P> <P> The Indus Valley Civilisation is also named the Harappan civilisation after Harappa, the first of its sites to be excavated in the 1920s, in what was then the Punjab province of British India . The discovery of Harappa, and soon afterwards Mohenjo - daro, was the culmination of work beginning in 1861 with the founding of the Archaeological Survey of India in the British Raj . Excavation of Harappan sites has been ongoing since 1920, with important breakthroughs occurring as recently as 1999 . This Harappan civilisation is sometimes called the Mature Harappan culture to distinguish it from the cultures immediately preceding and following it . Of these, the earlier is often called the Early Harappan culture, while the later one may be referred to as the Late Harappan, both of which existed in the same area as the Mature Harappan Civilisation . The early Harappan cultures were preceded by local Neolithic agricultural villages, from which the river plains were populated . A total of 1,022 cities and settlements had been found by 2008, mainly in the general region of the Indus and Ghaggar - Hakra Rivers, and their tributaries; of which 406 sites are in Pakistan and 616 sites in India; of these 96 have been excavated . Among the settlements were the major urban centres of Harappa, Mohenjo - daro (UNESCO World Heritage Site), Dholavira, Ganeriwala and Rakhigarhi . </P> <P> The Harappan language is not directly attested, and its affiliation is uncertain since the Indus script is still undeciphered . A relationship with the Dravidian or Elamo - Dravidian language family is favoured by a section of scholars . </P>

What is the name of the recently discovered central asian urban society from ca. 2200 b.c.e