About 10 million men, women and children were participating, joining tens of millions of others who bathe in rivers on different days as part of the Maha Khumbh Mela, an event described on official websites as the largest religious gathering on Earth.
It is held once every 12 years.
This year's event, which began last month and lasts through February, is drawing Hindus from all over the world and tens of thousands of foreign tourists.
Khumbh means an open-mouthed pitcher and Mela means a fair. Hindus believe drops of nectar spilled from the Kumbh as it was being carried by the gods after they had churned the oceans for the divine liquid. The Allahabad Sangam was one of the places where one of the drops fell into its rivers. Bathing in those rivers is believed to cleanse all sins and liberate a person's soul from the eternal cycle of life and death.
Friday was the day of Basant Panchami Snan, one of the most auspicious parts of the entire event when millions of Hindus bathe at the Triveni Sangam in Allahabad city in northern Uttar Pradesh state. The Sangam is the confluence of the Ganges,Yamuna and mythical Saraswati rivers.
The BBC said at least 100 million bathers were expected to participate in this year's 55-day festival, which was hit this week by tragedies,including a railway station stampede that killed dozens of people.
The NDTV television channel reported a fire broke early Friday in a tent, killing one person.