“No material culture is found to move from west to east across the Indus.”
in the relevant time period
Source: Jim Shaffer. Personal communication (to K. Elst) during the 1996 Indus-Saraswati conference in Atlanta GA., quoted in Elst, Koenraad (1999). Update on the Aryan invasion debate https://web.archive.org/web/20100412074243/http://www.bharatvani.org/books/ait/ New Delhi: Aditya Prakashan.