Which regions were the earliest known settlement areas of Indo-Aryan speakers in the Indian subcontinent?

Based on geographical references in the Rigveda—the earliest Indo-Aryan literary document—scholars widely agree that the earliest known settlement area of Indo-Aryan speakers in the Indian subcontinent was in the northwest, specifically the Punjab region.12

While the exact nature and timing of their arrival remain subjects of academic discussion, the prevailing view is that these speakers entered the subcontinent from the northwest during the late 3rd and 2nd millennia BCE. This migration is now understood by modern scholarship as a series of movements rather than a singular invasion. Although some alternative theories suggest an indigenous origin for these populations within the subcontinent, the linguistic evidence is generally reconciled with the thesis that Indo-Aryan speakers arrived from an external homeland, eventually spreading eastward and southward across northern India.321