Suggested contributory causes for the localisation of the IVC include changes in the course of the river, and climate change that is also signalled for the neighbouring areas of the Middle East. many scholars believe that drought, and a decline in trade with Egypt and Mesopotamia, caused the collapse of the Indus Civilisation. The climate change which caused the collapse of the Indus Valley Civilisation was possibly due to "an abrupt and critical mega-drought and cooling 4,200 years ago," which marks the onset of the Meghalayan Age, the present stage of the Holocene.