The Kumbh Mela festival, the largest religious gathering in the world, has begun in the northern Indian city of Prayagraj.

Swami Bhupender Giri, centre, Naga Sadhu of Niranjani Akhara, arrives for ritualistic dip at Sangam, the confluence of the Rivers Ganges, Yamuna and mythical Saraswati on one of the most auspicious day Makar Sankranti,

India's Maha Kumbh Mela, or Great Pitcher Festival, is set to be the world's largest gathering of humanity, with 400 million visitors expected at the six-week event that began this week in the northern city of Prayagraj.

Over the coming 45 days, an estimated 400 million Hindus are expected to come together for Maha Kumbh Mela. The festival is held every 12 years but the "Maha" or grand Kumbh Mela takes place only every 144 years, "marking the 12th Kumbh Mela and a special celestial alignment of the sun, moon and Jupiter", said The Guardian.

By Saurabh Sharma PRAYAGRAJ, India (Reuters) -Naked Hindu ascetics smeared in holy ash charged into the waters of sacred rivers in India on Tuesday, part of a large crowd of 35 million devotees who took the holy dip on the second day of the Maha Kumbh Mela,

India's Mahakumbh Mela, which is the world's largest religious gathering, entered its second day. Over the next six weeks, 400 million visitors are expected to attend the festival. Thousands of religious leaders and pilgrims could be seen charging into the icy waters in a ritual they believe will cleanse them of sin and help them achieve salvation.

Millions of Hindu pilgrims gathered on Tuesday at the confluence of the Ganges, Yamuna and Sarasvati rivers to take part in the first holy bath of the Kumbh Mela, the world's largest religious gathering.