"Jhamu Yatra" is a festival celebrated in the month of Chaitra (April-May) in many villages of Orissa in India.

It is associated with the worship of Shakti and Shiva and is believed to have come from the mass religious culture of Tantra from Orissa's ancient past.

To the accompaniment of loud drumming, the clash of cymbals , chanting and holy cries , 'patuas' or holy devotees who are from lower castes , move around the village in a ritual procession after going into a trance.

Nian patuas ( 'Nian' for fire ) observe a vow in honour of the deity and are carried in palanquins around the village and the temple. 

The patuas , who remain in a trance during the ritual , connect to a different level of consciousness and exhibit amazing oracular and supra-physical abilities.

After being carried around the village ritually , the oracles bow down in front of the shrine of the village deity, in this case the Goddess Jagulei.

Meanwhile, a long pit filled with glowing embers is prepared in front of the village temple.

At Gara-di-panchana village , this is the ancient Shiva temple , the Buddhanatha temple.

All the villagers, men, women and children, gather in front of the temple.

As the oracles arrive , they are greeted with holy cheers and ululation by the crowd.

The flames and smoke from the blowing embers in the pit, the incense and music, the cries of the onlookers , all come together to create an extraordinary spectacle.

It is now time for the Nian patuas to exhibit the powers from which they get their name.

They get down from the palanquins and fire-walk barefeet through the glowing embers several times , in an awe inspiring tableau of faith and supernatural power.

Though the fire walkers clearly tread on the embers in the smoking pit, they show no signs of being touched by the fire.

If they happen to answer any question put to them in this state of heightened consciousness , their prophecies usually come true.

I got some of the background information from here :

http://www.indiantravelportal.com/orissa/festivals/hingula-yatra.html