Narayan Nagbali consists of two different rituals. Narayan bali is done to get rid of ancestral curse (Pitru dosh /Pitru Shaap) while Nag bali is done to get rid of sin performed by killing snake, specially Cobra which is worshipped in India. It can be performed only at Trimbakeshwar.
Narayan Bali ritual is done to fulfill the unsatisfied desires of the ancestral souls which are stuck in the world and trouble their progeny. Narayan Bali consists of the same ritual as Hindu funeral. An artificial body mostly made of wheat flour is used. Mantras are used to invoke such souls who are having certain wishes remaining attached. The ritual makes them possess the body and the funeral frees them to other world.
Nagbali ritual is done to get rid of sin of killing nag (Cobra). In this ritual also the funeral is performed on the body of snake made with wheat dough. Narayan Nagbali is one of the main rituals performed at Trimbakeshwar. Ancient scriptures like Dharma Sindhu, which describes various religious rites, mentions that this particular ritual should be done only at Trimbakeshwar. The references are found even in Skandh Puran and Padma Puran about this age-old tradition.
It gives good health, success in business and career and fulfils wishes. It is a three day ritual on a particular day and time (muhurta). On the first day, the devotees should take a holy bath in Kushavarta and resolve to give dashdaan (give ten things in charity). After offering prayers at the Trimbakeshwar temple, they go to the dharmashala at the confluence of rivers Godavari and Ahilya for performing Narayan Nagbali.
Narayanbali-Nagbali pooja is performed at Trimbakeshwar only. This puja is performed in three days. This puja needs a special dates to perform it. Some days are not suitable to perform this puja. This puja is performed for so many reasons. If one has suffering from illness, going through bad times, someone in family has killed Nag (cobra). Or one is having a problem to have a kids or just you have everything and you want to perform some religious puja to have everything.