The police said that unknown men planted explosives in a cement pipe placed along road which exploded when a motor rickshaw was passing by.
"Resultantly, four persons sustained injuries in the blast," the police said, adding that the injured include a motor rickshaw driver and three pedestrians.
The rescue teams rushed to the scene and shifted the wounded to hospital for medical treatment.
There was no immediate claim for the responsibility of the blast. According to bomb disposal squad, Improvised Explosive Device was used in the blast.
The law enforcement agencies have cordoned off the entire area to trace the suspects. Further probe was underway.