The former centre halfback died around 12.30 am at his residence in Santoshpur, Kolkata.
Datt was a part of India's golden era in hockey.
A formidable halfback, he was part India's historic feat at the 1948 Olympics where they beat home team Britain 4-0 at the Wembley Stadium in London to win the primary gold post Independence.
Before the 1948 Olympics, Datt had toured East Africa under the leadership of hockey wizard Major Dhyan Chand in 1947.
Born on December 29, 1925 in Lahore, Datt was also a part of the Indian team at 1952 Helsinki Games, where they beat Netherlands 6-1 within the summit clash to become the Olympic champions for the fifth consecutive time.
"We are all very sadden to listen to about the legendary halfback Keshav Datt's demise early this morning. He was the lone surviving member of the 1948 and 1952 Olympic Games and today truly seems like the top of an era", said Hockey India President Gyanendro Ningombam during a statement.
We all grew up taking note of incredible stories of their memorable outings for independent India at the Olympics and that they went on to inspire generations of hockey players within the country.
"Hockey India mourns his demise and on behalf of the Federation I extend my deepest condolences to his family".
West Bengal Chief Minister Mamata Banerjee also offered her condolences.
"The world of hockey lost one among its true legends today. Saddened at the death of Keshav Datt. He was a double Olympic trophy winner, 1948 and 1952. A champion of India and Bengal. Condolences to his family and friends", Banerjee tweeted.
An integral a part of the Indian team, Datt also captained the Mohun Bagan hockey squad from 1951-1953 and again in 1957-1958.
As a Mohun Bagan player he won the league sixfold and Beighton Cup 3 times during a span of 10 years.
He was conferred with the Mohun Bagan Ratna award in 2019, becoming the primary non-footballer recipient of the honour.
