In order to release your vehicle from the custody of police you will have to file an application under Section. 457 of the Code of Criminal Procedure before the jurisdictional magistrate of your area. You will get a date of hearing and will have to appear before the court along with all the necessary document pertaining to your vehicle.
You will have to undergo this process within six months from the date of seizure. After hearing your case, the magistrate may pass an order to release your vehicle. However, the police would not have seized your vehicle without any reason. You may have unknowingly violated any particular traffic violation because of which your vehicle was seized.
You may have to pay the fine or undergo punishment for the particular offence you committed. Also, in order to release your vehicle, the magistrate may ask you to pay an indemnity bond or a surety bond.
After an order is passed by the magistrate, you may go to the police station where your vehicle is currently is and furnish the order passed by the magistrate to the officer in charge in the police station. After verifying the documents, the officer will release your vehicle.
Reference: Section. 457, Code of Criminal Procedure