Sacred and political: Over 100 million people to attend Kumbh mela in Jan

Organisers are erecting temporary bridges, 600 mass kitchens, more than 100,000 portable toilets

Spirituality, politics and tourism: welcome to the Kumbh Mela, the world's largest gathering of humanity, that begins next month in India.

During the Kumbh Mela, to be held in Prayagraj in Uttar Pradesh, millions of pilgrims including naked, ash-smeared ascetics, will bathe at the confluence of the Ganges, the Yamuna, and a mythical third river, the Saraswati.

Devout Hindus believe that bathing in the waters of the Ganges absolves people of sins and bathing at the time of the Kumbh brings salvation from the cycle of life and death.

The government says about 100 million to 150 million people, including