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

Days before India started its mammoth Kumbh Mela festival, a video showing preparations for a nighttime light show surfaced in social media posts that falsely linked it to the six-week Hindu event. The video was in fact originally published by a US-based drone show company and shows a Christmas celebration.

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,

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.

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.

An estimated 40 crore people are expected to attend the Maha Kumbh in Prayagraj this year with the Uttar Pradesh government earmarking a budget of Rs 6,990 crore for the gathering.