Sunanda's 21-year-old son Shiv Menon lit the pyre.
Pushkar's husband Union minister Shashi Tharoor, her father and brother were among the family members present at the Lodhi Road crematorium.
Earlier, her body was taken from AIIMS to Tharoor's residence at Lodhi Estate where a number of prominent political leaders including Defence Minister A K Antony, Overseas Indian Affairs Minister Vayalar Ravi and former Delhi Chief Minister Sheila Dikshit paid tributes to her.
Shiv, who performed the last rites, is Sunanda's son from previous marriage.
A three-member panel of doctors headed by Dr Sudhir K Gupta had conducted an autopsy on Sunanda's body in AIIMS.
52-year-old Sunanda was found dead in her suite at the Leela Palace hotel on Friday evening and the body was shifted to AIIMS at around 3:30 AM for post-mortem.
Sunanda and Tharoor were at the centre of a raging controversy when reports emerged that she was upset over reported text and tweet messages between her husband and Mehr Tarar, a Pakistani journalist.