I brought my car with me from rajasthan to delhi .Now I planning to re register the vehicle with Delhi RTO after 11 months.Now I intend to fit LPG kit in the car.Where should I get permission for this, from delhi RTO of rajasthan RTO?

For installing LPG kit in your car, you need permission from the R.T.O. under section 52 of Motor Vehicles Act. Get permission from local RTO of your area in rajasthan.