Explanation:

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.