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.

It’s late evening in the city of Prayagraj and the roadside vendors selling snacks are packing up their wares to shut for the night.

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.