Sister Nirmala, who took over Mother Teresa's charity mission in India, dies at 81

Sister Nirmala in Kolkata, India, on Dec. 11, 2004. (AP / Bikas Das)

KOLKATA, India -- The Indian nun who replaced Mother Teresa as head of the Missionaries of Charity died Tuesday, the organization said. Sister Nirmala Joshi was 81.

Her health had been declining in recent days, the charity said. It did not give more details about the cause of her death.

She was selected to lead the Roman Catholic charity six months before the death of its founder, Mother Teresa, in 1997. She remained its leader, or superior general, until stepping down in 2009. That year, she also received India's second-highest civilian award, the Padma Vibhushan, in honour of her service to the nation.

She was born to Hindu parents in 1934 in the northern Indian city of Ranchi, now the capital of the state of Jharkhand, before India gained independence from the British Empire. She reportedly converted to Roman Catholicism after being educated by Christian missionaries and learning of Mother Teresa's work.

Indian politicians including Prime Minister Narendra Modi and opposition Congress party leader Sonia Gandhi praised her work for the poor in the eastern city of Kolkata, where the charity is based.

"Sister Nirmala's life was devoted to service, caring for the poor and underprivileged," Modi said in a statement, adding that he was "saddened by her demise. May her soul rest in peace."

West Bengal's highest elected official, Chief Minister Mamata Banerjee, said in a Twitter message that "Kolkata and the world will miss her."

The Vatican newspaper, l'Osservatore Romano, paid homage to Nirmala in a long obituary, noting that she was elected superior of the order even though she had an incurable form of malaria that gave her constant fevers.

A funeral was planned for Wednesday at the charity's Kolkata headquarters, called the Mother House.

Mother Teresa received the 1979 Nobel Peace Prize for her charity work and is considered a candidate for Catholic sainthood.