A bathing festival worshipper was killed when a bus burst into flames in India.

The elderly passenger was burned to death after a private tourist bus carrying at least 50 pilgrims caught fire in Vrindavan, Mathura district of Uttar Pradesh, on January 14.

Local media reported that the group had embarked on a pilgrimage to the Mahakumbh Mela, a Hindu festival held every 12 years.

The bus was reportedly parked at a tourist centre while the passengers were visiting a temple when it went up in flames.

Dramatic footage shows the vehicle engulfed in a massive fire, with plumes of smoke rising upwards.

Sheelam Dharupath, 60, was left on the bus when the incident happened.

Authorities said the victim sustained burns to 90 per cent of his body.

Officials speculated that a lit beedi may have caused the blaze, though a detailed investigation is ongoing.

Mahakumbh Mela is regarded as the largest human gathering on Earth, celebrating India's rich cultural and spiritual traditions.

This year, at least 450 million devotees are expected to participate in the holy dip during the 45-day event.