Ghost-Eye by Amitav Ghosh

Calcutta, September 1969Varsha Gupta wants fish for her lunch. Her family can't understand it; the three-year-old has never tasted fish in her life. The Guptas are strict vegetarians and don't allow it inside their Calcutta mansion. But Varsha claims she can remember another life, a mud house by a river where she caught and cooked fish with a different mother. Perplexed, the Guptas turn to Dr. Shoma Bose, a psychiatrist who has been investigating what are known as 'cases of the reincarnation type' for years. But her understanding of the world is changed forever by Varsha's revelations. Half a century later, Varsha's therapeutic case file catches the attention of a group of environmental activists, and Shoma's nephew Dinu is drawn inexorably into their plans. And as Dinu finds himself caught up in the search for Varsha, buried memories of his own past begin to surface.