Recently back in the year 2007 the Ardha Kumbh was celebrated after a wait of 6 years and according to the Mela committee a whooping 70 million people took the holy bath in the waters of the Ganges at Allahabad that took place for about 45 days. The four places are famous for the holy ritualistic bathing namely the Allahabad, Haridwar, Ujjain and Nasik.
The festival has been organised from a very long back. The evidence can be found in the accounts of the foreign Chinese traveller Hieun Tsang, who visited the court of the king Harshavardhan around the time 629-645 AD. It is known to be the first written account of the Kumbh Mela though many such evidences of the gatherings on the river banks can be found mentioned in the various scriptures and the texts of the Hindus.
The mythology says that during the churning of the waters of the ocean the pot of the holy amrita came out and which contained the liquid that could give a immortal life. So a fight for the amrita started between the demons and the gods and a few drops of the amrita spilled and fell at the four places mentioned above viz. Allahabad, Nasik, Ujjain and Haridwar and these became the places for the holy dipping in the waters.
These days a lot of consciousness among the people has developed in case of the hygiene that is to be maintained for a clean and a healthy bathing. The waters of the Ganges is considered to be very holy due to its very high level of the oxygen content but due to the pollution that is caused by the pouring of the outlets of the factories into the river. There had been an upsurge among the hermits that live in and around the ghats of the places where the holy dip takes place in order that the government may take a strong action to clean the river.
At the Kumbha melas we find a variety of the people coming to take the bath. The interesting of them are the so called "naga babas" who are the people who have devoted their lives to the lord Shiva the god of destruction in according to the Hindu mythology. They discard all their clothes and remain fully naked and cover their body in the ash. The naga babas are considered very much powerful in terms of wisdom and spirituality. They usually abstain from speaking to people. the first right to take the holy dip at the Kumbh is of the "Naga Babas" as soon as the bathing begins and then it is opened to the other people.