Ramdev told the media here that BJP's prime ministerial candidate Modi was the best leader in India, describing Congress vice president Rahul Gandhi as a "failure" and Kejriwal as a "turncoat".
Kejriwal, he said, lagged far behind other regional leaders like Chief Ministers J. Jayalalithaa, Mamata Banerjee and Naveen Patnaik.
"If he (Delhi Chief Minister Arvind Kejriwal) had asked me at that time, we would have asked the BJP to support him," Ramdev said.
Ramdev added that Kejriwal had damaged his reputation by indulging in "nautanki" (theatrics) and by taking repeated U-turns on issues such as the use of a car after assuming charge as chief minister.
"On the first day he used an auto. Then he used a Wagon-R and now he is using an Innova. At least he should have used an Indian car like the Nano," Ramdev said.
The yoga guru said he himself uses only vehicles made in India.
Ramdev said that by taking the support of "one of the most corrupt parties in India", the Congress, Kejriwal had betrayed his promise to fight corruption.
He said only Modi was "strong, effective and capable of delivering good governance".
"Rahul Gandhi is a failure... The Congress will not win even 50-60 seats in the Lok Sabha election."