Conversation so far:
What are the origins of the Vedic period?
After the collapse of the Indus Valley Civilisation, which ended circa 1900 BCE, groups of Indo-Aryan peoples migrated into north-western India.

Question: What were differences after inhabiting the northern Indus Valley?
Self-contained rewrite: What were differences after groups of Indo-Aryan peoples started inhabiting the northern Indus Valley?