"Prime Minister Manmohan Singh must be knowing that money grows under the earth in the form of coal. Therefore, he said that money does not grow in trees," Ramdev said on the sidelines of a function here.
Demanding punishment for the persons involved in alleged irregularities in coal block allocation, Ramdev said "Coal scam is the biggest ever scam in the world as Rs 400 lakh crore is involved in it."
He also reiterated his demand of bringing back black money stashed abroad.
Replying a question on his 'friend' Naveen Patnaik, Ramdev said "I have no friendship or enmity with anyone. I am a fakir. Whoever is involved in corruption must be punished."