Kumbh Mela Mythologial Origin
Kumbha Mela and Sinhastha Yatra at Trimbakeshwar. When Gods and Demons churned the ocean, along with diamonds, Amrit Kumbha (Urn containing Nectar) were recovered. Lord Indra's son Jayant was appointed to guard and deliver the same in heaven. He was helped by Sun , Moon, Saturn and Jupiter. On there way to heaven Gods were attacked 4 times by the evil spirited demons. Gods were successful in retaliating the attacks and placed the Kumbha on earth for each attack. The four places where the Kumbha was placed are Nasik, Haridwar, Prayag (Alhabad), Trimbakeshwar and Ujjain.
Kumbha Parva or Mela is celebrated according to the celestial alignment of zodiac signs,with Jupiter, this is because Jupiter was in alignment with some signs at the time when Kumbha was plased at above said four places.
According to medieval Hindu theology, the origin of the festival is found in one of the most popular medieval puranas, the Bhagavata Purana. The Samudra manthan episode (Churning of the ocean of milk), is mentioned in the Bhagavata Purana, Vishnu Purana, the Mahabharata, and the Ramayana. The traditional account says that the Devas had lost their strength by the curse of Durvasa Muni, and to regain it, they approached Lord Brahma and Lord Shiva.
They directed all the demigods to Lord Vishnu and after praying to Lord Vishnu, he instructed them to churn the ocean of milk Ksheera Sagara (primordial ocean of milk) to receive amrita (the nectar of immortality). They had to make a temporary agreement with their arch enemies, the Asuras, to work together with a promise of sharing the wealth equally thereafter. However, when the Kumbha (urn) containing the amrita appeared, a fight ensued. For twelve days and twelve nights (equivalent to twelve human years), the Devas and Asuras fought in the sky for the pot of amrita. It is believed that during the battle, Lord Vishnu (incarnated as Mohini-Mürti) flew away with the Kumbha of elixir, spilling drops of amrita at four places: Allahabad (Prayag), Haridwar, Ujjain, and Nashik