How does Shradh in Gaya liberate ancestors from Pitru Dosh?

Shradh performed at Gaya is scripturally considered the most powerful single remedy for Pitru Dosh (ancestral affliction) in Vedic astrology. The Vayu Purana explains the mechanism: Pitru Dosh arises when ancestors are trapped in Preta state or are unsatisfied due to missed Shraddhas, unresolved karma, or the absence of Pind Daan. When Shraddha is performed at Gaya with correct procedure, the following happens: (1) Lord Vishnu personally accepts the offerings through the Vishnupad footprint, (2) The pindas are carried by the Phalgu River to Pitru Loka, (3) Ancestors receive direct nourishment and are released from their trapped state, (4) The root cause of Pitru Dosh in the performer’s birth chart is neutralised, (5) The karmic debt owed by the descendants to their ancestors is symbolically repaid. This is why Gaya Shradh is often the prescribed remedy when Pitru Dosh is diagnosed in a Kundali.