Kumbh Mela or Kumbha Mela is a mass Hindu pilgrimage of faith in which Hindus gather to bathe in a sacred or holy river. Traditionally, four fairs are widely recognized as the Kumbh Melas: the Prayagraj Kumbh Mela, Haridwar Kumbh Mela, the Nashik-Trimbakeshwar Simhastha, and Ujjain Simhastha. These four fairs are held periodically at one of the following places by rotation: Allahabad (Prayagraj), Haridwar, Nashik district (Nashik and Trimbak), and Ujjain. The main festival site is located on the banks of a river: the Ganges (Ganga) at Haridwar; the confluence (Sangam) of the Ganges and the Yamuna and the invisible Sarasvati at Allahabad; the Godavari at Nashik; and the Shipra at Ujjain. Bathing in these rivers is thought to cleanse a person of all their sins.
At any given place, the Kumbh Mela is held every 12 years. There is a difference of around 3 years between the Kumbh Melas at Haridwar and Nashik; the fairs at Nashik and Ujjain are celebrated in the same year or one year apart. The exact date is determined, following the Vikram Samvat calendar and the principles of Jyotisha, according to a combination of zodiac positions of Jupiter, the Sun and the Moon. At Nashik and Ujjain, the Mela may be held while a planet is in Leo (Simha in Hindu astrology); in this case, it is also known as Simhastha. At Haridwar and Allahabad, a Maha (“Great”) Kumbh Mela is held every 12 years, with an Ardha (“Half”) Kumbh Mela six years later. The priests at other places consider their local fairs to be Kumbh Melas; for example, the Mahamaham festival at Kumbakonam, held every 12 years, is described as a Kumbh Mela.Other places where fairs have been called Kumbh Mela include Kurukshetra and Sonepat.