Ramdev's statement that Gandhi goes to Dalit homes for "picnics and honeymoon" had kicked up a controversy recently.
"An FIR has been registered against Ramdev under the relevant sections of (SC/ST Prevention of) Atrocities Act over his remarks," Narendra Singh, senior inspector at Azad Maidan police station, told PTI.
Urmila Pawar of Mahila Haq Sangharsh Samiti had approached the police with a written application seeking action against Baba Ramdev the day before yesterday, Singh said.
Police sought a legal opinion on the issue and then the FIR was registered against the yoga guru, he added.