In Hindu tradition, it is thought that a person is born with three debts:
Deva rina (debt to God), Acharya rina (due to Guru), and Pitru Rina (respect for elders and forebears)
The purpose of the Pitru Paksha is to honour our deceased ancestors by doing rituals that will remove the Pitru Rina, assure their salvation (moksha), and benefit both, us and them. “Pitru” stands for ancestors, while “Paksha” is the moon cycle. For the purpose of conducting pindadaan, shradh, and tarpan for the ancestors, the 15 days of the dark fortnight (krishna paksha) in the lunar month of Bhadrapada (according to the lunar calendar) or the solar month of Ashwin (according to the solar calendar) are referred to as Pitru Paksha. Sarva Pitru Amavasya
Author-Gopi Shah