In India, any alteration made to the engine or basic structure of a motor vehicle after it has been registered with the Regional Transport Office (RTO) is considered unauthorized and illegal. The Central Motor Vehicles Rules, 1989, specify that any alteration to the structure or engine of a motor vehicle requires prior approval from the RTO.
If a motor vehicle is found to have unauthorized post-registration alterations to its engine or basic structure, the driver/owner of the vehicle may be fined. The fine amount may vary from state to state, but it can range from Rs. 5,000 to Rs. 10,000 or more depending on the type of violation.