The lioness "Meera" was brought to BNP after being rescued from a circus company in Haryana's Faridabad in 2001.
She was not consuming food for the past one week, BNP Executive Director Taggore Milo said in a statement.
Post mortem report revealed the cause of death to be "acute pneumonia, calcification of the lung and and multi-organ failure", the statement said.
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