A research conducted by IIT Kharagpur on Indus Valley Civilization

A study by Indian researchers at major excavated site of Bhirrana, Haryana suggests that the Indus Valley Civilization is much older than thought before and climate was not only the cause behind collapse of Harappa civilization.

The study was conducted by a research team from IIT Kharagpur, Institute of archaeology, Deccan College Pune, Physical Research Laboratory and Archaeological Survey of India.

The finding was published in prestigious journal Nature Scientific report on 25 May 2016.

Dated Potteries as old as 8000 years old
• Bhirrana site shows preservation of all cultural levels of Indus Valley Civilization from Pre-Harappan Hakra phase through Early Mature Harappan to mature Harappan time
• The study of dated potteries of Early Mature Harappan time by a technique called optically stimulated luminescence (OSL) suggests that these were nearly 6000 years old, the oldest known pottery so far.
• The study of levels of Pre-Harappan Hakra phase was dated to be as old as 8000 years.
• This means that the Indus Valley civilisation is 2500 years older than previously believed and the Indus Valley settlements that spread across Pakistan and northern India is older than the Mesopotamian and Egyptian civilisations.

Climate Change not led to abrupt collapse of Harappa civilization
• Researchers used oxygen isotope composition in the bone and tooth phosphates of these 2 remains found at Bhirrana to unravel the climate pattern.
• The study revealed that the monsoon became progressively weaker from 7000 years onwards but surprisingly the civilization did not disappear, rather they continued to evolve even in the face of declining monsoon condition.
• In the event of weakening of monsoon changed their subsistence strategy. They shifted their crop patterns from the large-grained cereals like wheat and barley to drought-resistant species of small millets and rice.
• As a result of lower yield of these later crops the organized large storage system of mature Harappan period was abandoned. In its place more individual household based crop processing and storage system arose.
• It is this factor which could have acted as catalyst for the de-urbanisation of the Harappan civilization rather than an abrupt collapse.

Harappa site Bhirrana
• It was excavated by late Dr. LS Rao in 2005-2006.
• Bhirrana was part of a high concentration of settlements along the now dried up mythical Vedic river valley 'Saraswati', an extension of Ghaggar river in the Thar Desert.
• It shows preservation of all cultural levels of Indus Valley Civilization from Pre-Harappan Hakra phase through Early Mature Harappan to mature Harappan time.
• While the earlier phases were represented by pastoral and early village farming communities, the mature Harappan settlements were highly urbanized having trans-Asiatic trade with Arabia and Mesopotamia.

Background
• The present studies put the flourishing of post-Neolithic Bronze Age Harappan civilization between 5700-3300 BC.
• It spread along the Indus Valley of Pakistan through the plains of NW India, including into the state of Gujarat and up to the Arabian Sea.
• In the Indian subcontinent the major centers of this civilization include Harappa and Mohenjo-Daro in Pakistan and Lothal, Dholavira, Kalibangan and Rakhigarhi in India.
• Many archaeologists believe that weakening of the summer monsoon after ~5000 years and a major drought around 4200 years throughout the Asia probably were the reason behind the Harappan collapse.
• The late Harappan phase witnessed large scale deurbanization, population decrease, abandonment of many established settlements, lack of basic amenities, interpersonal violence and disappearance of Harappan script.