Kumbh Mela or Kumbha Mela (ˌkʊmb_ˈmeɪlə) is a major and festival in Hinduism. It is celebrated in a cycle of approximately 12 years, to celebrate every revolution Brihaspati (Jupiter) completes, at four river-bank pilgrimage sites: Prayagraj (Ganges-Yamuna-Sarasvati rivers confluence), Haridwar (Ganges), Nashik (Godavari), and Ujjain (Shipra). The festival is marked by a ritual dip in the waters, but it is also a celebration of community commerce with numerous fairs, education, religious discourses by saints, mass gatherings of monks, and entertainment. The seekers believe that bathing in these rivers is a means to prāyaścitta (atonement, penance) for past mistakes, and that it cleanses them of their sins.
The festival is traditionally credited to the 8th-century Hindu philosopher and saint Adi Shankara, as a part of his efforts to start major Hindu gatherings for philosophical discussions and debates along with Hindu monasteries across the Indian subcontinent. However, there is no historical literary evidence of these mass pilgrimages called "Kumbha Mela" prior to the 19th century. There is ample evidence in historical manuscripts and inscriptions of an annual Magha Mela in Hinduism – with periodic larger gatherings after 6 or 12 years – where pilgrims gathered in massive numbers and where one of the rituals included a sacred dip in a river or holy tank. According to Kama MacLean, the socio-political developments during the colonial era and a reaction to Orientalism led to the rebranding and remobilisation of the ancient Magha Mela as the modern era Kumbh Mela, particularly after the Indian Rebellion of 1857.
The weeks over which the festival is observed cycle at each site approximately once every 12 years based on the Hindu luni-solar calendar and the relative astrological positions of Jupiter, the sun and the moon. The difference in Prayag and Haridwar festivals is about 6 years, and both feature a Maha (major) and Ardha (half) Kumbh Melas. The exact years – particularly for the Kumbh Melas at Ujjain and Nashik – have been a subject of dispute in the 20th century.