"...I understand perfectly that all religious scriptures except the ones related to hinduism ,sikhism and buddhism prescribe death penalty for blasphemy ..."

Manusmriti, the Law book of the Hindus, it says:

“If a man born of a lower class intentionally bothers a priest, the king should punish him physically with various forms of corporal and capital punishment that make men shudder.” [Manusmriti 9:248]