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

India began on Monday its Maha Kumbh Mela, or Great Pitcher Festival, which is expected to draw more than 400 million visitors to the northern city of Prayagraj over six weeks, making for the largest gathering of humanity in the world.

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.

Organisers of India's Kumbh Mela have prepared to host a staggering 400 million devotees at the six-week Hindu festival that starts Monday and is expected to be the largest human gathering in history.