Singh breathed his last at 0820 hrs on Thursday.
He is survived by his son Jayant and two daughters.
On April 20, Singh tested positive for the deadly virus. His condition deteriorated on April 22 after his lungs developed an infection.
Son of former prime minister Late Chaudhary Charan Singh, Ajit Singh, a farmer leader of Western UP had lost the Lok Sabha polls in 2019 from Baghpat.
Ajit Singh's son Jayant Chowdhury is presently leading the party and in alliance with Samajwadi party, it performed excellent in the Panchayat polls in western UP.
Prime minister Narendra Modi, UP Chief Minister Yogi Adityanath, Defence Minister Rajnath Singh and others have condoled the death. (UNI)