JANAKPUR: A man was seriously injured in a bomb explosion at a house located in Campus Chok of Janakurp Sub-Metropolitan City on Saturday morning. The house was of Naresh Yadav. The injured one is identified as Shrawan Yadav (20) of Gauripur-9 of Siraha district, currently living in Naresh' house on rent. According to police, the bomb that was kept at a lunch box was exploded from the room that was locked for one and half months. Further investigation regarding the case is on, informed police.