The judges' unanimous choice, "The Seven Moons of Maali Almeida" is the darkly humorous story about a murdered war photographer investigating his death and trying to ensure his life's legacy.
The award-winning author said her mother, the renowned educationalist, who died Thursday, was a miracle.
'The Satanic Verses' writer was stabbed in the neck and torso on Friday at an event in New York by a 24-year-old New Jersey resident Hadi Matar.
Tomb of Sand houses many good people. The source of the goodness of humanity in the world of the novel comes from the warm, hopeful, radiant personality of the author.
In a congratulatory message, Prof Mansoor said it is rare that a novel from a non-European language got the highest honour and it is the acknowledgement of Indian cerebral power.
Tomb of Sand, originally 'Ret Samadhi', is set in northern India and follows an 80-year-old woman in a tale the Booker judges dubbed a joyous cacophony and an 'irresistible nove'".
The shortlist of six books will be announced on September 14. The 2021 winner will be announced on November 3.
The book, based on the author's own childhood, tells of a young boy growing up during tough years in Glasgow with a mother who is battling addiction.
Though five of the writers are from America, it is a shortlist that carries the tang not just of America but of Scotland, Ethiopia, Zimbabwe and India too.
International Booker Prize is separate from the main Booker Prize, and aims to encourage more publishing and reading of quality fiction from around the world.