The trade of wheat, spices, silk, gold and pottery. Ancient trade routes traveled northeast with monsoon winds down the Red Sea returning back south-east. This was well traveled important route.
Decline of the Indus Valley people were peaceful people. There were no weapons found. It is believed they could have been conquered by Aryans people. Another belief is earthquake could have changed the landscape so much that he rivers were rerouted, and people either died or move to another location. Because of the overpopulation they would not be able to survive without water, climate change.
Aryans, Indo-European, nomadic coming from the West and North and fighting and conquering to the East.
hymns, prayers, chants, spells, 1500 500 BCE