Kavita, 57, had suffered a massive brain haemorrhage at her residence in central Mumbai on Saturday morning and was admitted at PD Hinduja Hospital, Mahim for treatment.
On Monday morning, her condition deteriorated and she slipped into coma.
“Kavita Karkare was declared brain dead on Monday morning," a statement released by the hospital in the morning read.
She did not recover after that and was subsequently declared dead.
Kavita was a professor at a B.Ed college in Mumbai but has stopped work recently.
She is survived by two daughters Jui and Sayali and son Akash.
They have consented to donate their mother's organ for the treatment of needy patients.
Kavita had been in the news for demanding better weapons, training and facilities for police personnel engaged in life-threatening situations after her husband died fighting terrorists.
Her husband, Hemant Karkare was the Anti-Terrorism Squad (ATS) chief during the 26/11 attack.
He was killed by terrorists near Mumbai's Cama Hospital, along with Additional Police Commissioner Ashok Kamte and senior police inspector Vijay Salaskar on the night of 26 November 2008.