Pitra Dosh

Manes are known as Pitra in Hindi. Pitra are those people who died unnatural death and did not get salvation. Due to this, people perform remedies for the pacification of Pitra Dosha. 
Manes who are creating problems also want to get relief from Pitra Yoni. This Dosha is formed if the young generat Pitra Dosha is formed if anyone in the family dies unnatural death or it happens many times. It can also happen if family members do not offer water and food to their manes or do not remember their manes in the spiritual activities. Pitra Dosha occurs if no one in the family is interested to perform spiritual tasks or if any family member kills a cow or destroys a foetus in the womb. In these situations, Sun and Rahu form conjunction in the ninth house in the birth chart of that person who is afflicted by Pitra Dosha. 
According to the Hindu scriptures, a person should worship his manes before the worship of deities because they have great importance. Therefore, you should satisfy your manes first to make the deities happy. Krishna Paksha of the Ashwini month as per Hindu calendar is the best duration for the pacification of manes.