At the confluence of the Ganges and the Yamuna a temporary city emerges to cater for tens of millions of Hindu pilgrims

What does the Kumbh Mela celebrate?

The Kumbh Mela is held at the four spots along the Ganges river where, Hindu tradition has it, drops of the nectar of immortality fell from an urn, or kumbh, that was being fought over by the gods and demons.

Tens of millions of pilgrims attend Kumbh Melas at these sites roughly every three years, praying the holy waters will emancipate them from the cycle of rebirth.

The festival in Prayagraj, Uttar Pradesh, where the Ganges and the Yamuna meet, has become the largest.

According to one set of Hindu holy books, the Puranas: “Those who bathe in the bright waters of the Ganga where they meet the dark waters of the Yamuna during the month of Magh [roughly January/February] will not be reborn, even in thousands of years.”

Hindus believe every soul passes through different lives (better or worse depending on your karma in the previous life) but the highest point is breaking out of the cycle, transcending it and achieving salvation/emancipation from the earthly life with its suffering and desires.

But the Kumbh Mela is also a vast market, meeting place and centre of learning, where people can attend spiritual lectures or take blessing from some of the country’s most-revered gurus, and Hindu saints are ordained.

How old is it?

Hard to say. A Chinese monk named Hsuan Tsang (or Xuanzang) described something that resembles the Kumbh Mela on the banks at Prayagraj in 643AD.

Festivals are thought to have been held at the confluence of the Ganges and Yamuna since ancient times, but historians have more recently argued the Kumbh in its modern form may have started around 1870, emerging from a power struggle between the Hindu clergy and the British colonialists.

How big is this thing?

It’s huge, even on an Indian scale. Nobody knows for sure, but organisers estimated 120 million attended the 2013 version in Prayagraj. That included an estimated 30 million on what was considered the most auspicious day for bathing.

An entire city about two-thirds the size of Manhattan (or 15 sq miles) emerges from the banks of the river to accommodate the numbers attending. This year, that includes 185 miles (300km) of roads and more than 120,000 toilets.

Facebook Twitter Pinterest Hindu holy men arrive en masse Photograph: Rajesh Kumar Singh/AP

What’s it like in the temporary city?

Overwhelming. It echoes with hundreds of musical performances, voices droning over loudspeakers, chants and prayers, the occasional trumpeting of an elephant and the din of millions of people. Holy men march past you in lines carrying coconut half-shells and wailing for alms; others sit in quiet repose, their bodies caked in ash. One priest was crouched on a corner wearing a loin cloth and aviator sunglasses, smoking hashish from a pipe, watched over by an Indian police officer carrying an automatic weapon. There is a palpably joyous atmosphere – if your senses manage to adjust.

What are the key moments?

It goes for more than 50 days, with four major bathing days throughout, but one key moment is the first day, when members of the main holy orders charge out into the river, often naked, roaring and smeared in ashes, to sanctify the waters and formally mark the beginning of the bathing.

These holy orders originally formed as armies to protect temples from invaders. Throughout the history of the festival, they have turned their weapons on each other, fighting armed battles over which order gets to enter the river first. In recent years, however, they have opted for dialogue to decide the schedule, but it is still a touchy issue and government officials are sometimes called in to help mediate.

Facebook Twitter Pinterest Devotees take a dip Photograph: Sanjay Kanojia/AFP/Getty Images

Does it have any resonance for India’s election this year?

Political parties have often sought to exploit the Kumbh Mela, though they have to be subtle – it is primarily a spiritual event after all.

Kumbh Mela: Hindus converge for largest-ever human gathering Read more

No Kumbh Mela has ever been quite so widely marketed as this one, with advertisements often featuring small pictures of the Indian prime minister, Narendra Modi. The fairgrounds are also plastered with billboards promoting his government’s social welfare programmes.

Modi’s Hindu nationalist party aims to unite Hindus behind a single political platform, something adherents have historically been reluctant to do, given how riven the religion is by caste and regional differences.

But the Kumbh Mela is indisputably moment of unity for Hindus, and that dovetails nicely with Modi’s political project, and so it can’t hurt to have such a giant iteration of the festival in an election year – especially if his picture is all over it.