She had succeeded Mother Teresa in 1997 as the superior general after the latter's death.
West Bengal chief minister Mamata Banerjee posted on Twitter about the huge loss and that the world would miss her.
Born in Ranchi on July 23, 1934, Sister Nirmala's father was a Brahmin soldier from Nepal. She joined the order at the age of 17. German-born sister Prema is now the successor of the deceased.