Khatarnak (2006)

Dasu is a small time crook who becomes orphan after his father goes to prison. Meanwhile a local goon decides to send one of his men into the police department to get information for them. Dasu will be roped for this job but he needs to pass SSC exam to get a police job. He clears the exam and gets into the force as a traffic cop. Then he is transferred to the crime branch because of his heroics. The rest of the story is about how Dasu realizes the sanctity of the cop job and eliminates the mafia gang.