Singh, a social activist, had a number of criminal cases against him, an Aam Aadmi Party leader said.
"There were criminal cases against him (Singh)," the AAP official said, adding that the party was earlier unaware of them.
According to the party official, Singh had spent "three months in jail last year in a case of fake currency circulation".
The party told him it was cancelling his nomination, and Singh agreed to it.
Social entrepreneur Khalid Parvez too won't be contesting from Moradabad after the party found out that he was a bank defaulter.
Rakhi Birla, who was the youngest minister in the Arvind Kejriwal government that lasted only 49 days and she will be fielded from the seat, a party leader told.