The explosion took place yesterday.
After examining the site and injured persons, police and scientific teams ruled out use of any explosive device or any criminal motive behind the blast and said some unexploded crackers dumped inside the dustbin by wedding procession parties went off.
Eye-witnesses said they heard a huge noise when the sweeper was taking out the garbage from the dustbin around 7.30 AM yesterday.
The sweeper Sulochana Dei (50) suffered burn injuries on her hand and face. Two athletes passing by the spot also received minor injuries.