HARDWAR, India (Reuters) - Millions of Hindus will rush to cleanse themselves of sin in India's holy Ganges river when the sun rises over the Himalayan foothills on Wednesday. Officials say up to three million people will jostle for position at bathing "ghats", or stepped banks, on either side of the Ganges river in the northern city of Hardwar, or "the gateway of god". The Kumbh Mela, or "pitcher festival", one of the world's largest religious celebrations, is held in rotation at one of four Indian cities every three years. Indian legend says Hardwar was one of four places where the nectar of immortality fell to earth after spilling out of a pitcher during an epic battle for its possession between gods and demons. The Guinness Book of Records cites the 1989 Kumbh Mela, at the confluence of the Ganges and the River Yamuna in Allahabad, which attracted 15 million devotees, as "the largest-ever gathering of human beings for a single purpose". Officials expect a total of 10 million people will converge at Hardwar to bathe in the chilly waters of the Ganges during the 15-week long festival of the Kumbh Mela, which ends on April 29. Hindus believe that bathing in a sacred river washes away their sins, speeding the way to the end of reincarnations in this world and the attainment of nirvana, or the after-life. A bathe at Hardwar, one of the holiest spots along the Ganges' 2,000-km (1,250-mile) journey from the Himalayas to the Bay of Bengal, during the Kumbh is considered most auspicious. Their faces smeared in ash, holy men scantily clad despite the icy winds sweeping the north Indian plains will bathe first, to the sound of conch shells. They will be followed by ordinary pilgrims, many of whom have accompanied ascetics and sect leaders to Hardwar in jubilant processions. The last Kumbh Mela at Hardwar was held in 1986, when nearly 60 people were killed in a stampede.