The blast occurred a little distance away from St Paul's School near Jalpaiguri town.
The injured people have been admitted to the Jalpaiguri District Hospital, said reports.
No group has claimed responsibility for the blast so far.
A police enquiry has been started into the matter.
Following the incident, North Bengal Development Minisiter Gautam Dev told media, "We will not tolerate it."
--IBNS (Posted on 26-12-2013)