While the ancient people relied upon heavy and regular monsoons between 9,000 and 7,000 years ago to water their crops, after this period, evidence at Bhirrana shows people continued to survive despite changing weather patterns.

‘Increasing evidences suggest that these people shifted their crop patterns from the large-grained cereals like wheat and barley during the early part of intensified monsoon to drought-resistant species of small millets and rice in the later part of declining monsoon and thereby changed their subsistence strategy,’ they continued.

However, changing the crops they grew and harvested resulted in the ‘de-urbanisation’ of cities and no need for large food storage facilities. Instead, the people swapped to personal storage spaces to look after their families.

‘Because these later crops generally have much lower yield, the organised large storage system of mature Harappan period was abandoned giving rise to smaller more individual household based crop processing and storage system and could act as catalyst for the de-urbanisation of the Harappan civilization rather than an abrupt collapse,’ the team wrote.