An explosion in a makeshift shed attached to a house near Nadakkavu in the city in the early hours of Tuesday caused concern among people in the area. The impact of the explosion blew the tarpaulin roof of the shed on to a tree top. There was no casualty in the incident. Windowpanes of a few houses near the Muthappankavu temple in Asokapuram (where the incident took place) were broken. The shed was used for storing spares parts of vehicles. Bomb and dog squads have been pressed into service.