People come to Allahabad to wash away their sins in the sacred River Ganges. For many it's the realization of their life's goal, and they emerge feeling joyful and rejuvenated. But there is also a darker side to the world's largest religious gathering, as some take advantage of the swirling crowds to abandon elderly relatives.

"They wait for this Maha Kumbh because many people are there so nobody will know," said one human rights activist who has helped people in this predicament and who wished to remain anonymous. "Old people have become useless, they don't want to look after them, so they leave them and go."

Anshu Malviya, an Allahabad-based social worker, confirmed that both men and women have been