"I start with some literary evidence. RV 4.1.13 & 4. 2.16 the Angirases declare that their ancestors made sacrifices “here” atra, ie in Saptasindhu. 3.53.11 Sudās fought enemies prāk ‘east’, apāk ‘west’ and udāk ‘north’ only, but not south. So we have no Indoaryans coming from the north and driving natives southward. The movement here is from east westward (apāk) and from south northword (udāk)! M6.61.9,12: Sarasvatī, the Rivergoddess, spread all five tribes beyond the other seven sister-rivers as the sun spreads out the days – again, days and sunlight from the east! 7.6.3 Agni turned the unholy Dasyus from east to west –pūrvaś cakāra áparām! Notice – NOT SOUTH (avāk or nyāk)."