Ideally, you should visit an orthopedic doctor who specializes in fracture, i.e. fracture treatment doctor in Kolkata.
(Remember, within orthopedics, there are specializations. For fractures, you don't want to go to a ligament specialist doctor in Kolkata. You want someone who specializes in treating fractures.)
That said, if you don't have a specialist in the neighborhood or nearby, visit your GP for the first line of treatment. Your general physician can recommend or refer you to an orthopedic specialist.