R Krishnakumar, a close aide of Ratan Tata and a group veteran, died Sunday evening, officials said.
Kerala-born Krishnakumar, who had served at multiple positions in the group, including heading its hospitality arm Indian Hotels, was 84.
The Padma Shri awardee suffered a heart attack at his home in the financial capital on Sunday, they said.
Tata Sons' current chairman N Chandrasekaran offered condolences for Krishnakumar's "enormous contribution" to the Tata Group.
"I had the good fortune of knowing him and what stood out was his deep sense of compassion as a human being. He always wanted to help the less privileged and positively impact their lives. We pray for his departed soul and will sorely miss him," Mr Chandrasekaran said in a statement.
Kerala Chief Minister Pinarayi Vijayan tweeted that Thalassery-born Krishnakumar helped strengthen the ties of the group with the southern state and offered condolences to the family.
Krishnakumar had been active with the Tata Trusts after his retirement from executive roles and was reportedly a part of the team which worked alongside Ratan Tata in the Cyrus Mistry ouster episode.
Krishnakumar's cremation will be held at Chandanwadi Crematorium here at 4.30 pm on Monday.
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