Robbery is an aggravated form of: 

IPC Section 390. Robbery—In all robbery there is either theft or extortion. When theft is robbery—Theft is “robbery” if, in order to the committing of the theft, or in committing the theft, or in carrying away or attempting to carry away property obtained by the theft, the offender, for that end voluntarily causes or attempts to cause to any person death or hurt or wrongful restraint, or fear of instant death or of instant hurt, or of instant wrongful restraint. When extortion is robbery—Extortion is “robbery” if the offender, at the time of committing the extortion, is in the presence of the person put in fear, and commits the extortion by putting that person in fear of instant death, of instant hurt, or of instant wrongful restraint to that person or to some other person, and, by so putting in fear, induces the person so put in fear then and there to deliver up the thing extorted