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

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.

One of the world's largest religious festivals is underway in India, the Kumbh Mela, which takes place every 12 years on the banks of several rivers including the Ganges. RNZ Asia's Gaurav Sharma explains the festival.