I have bought a diesel 520D luxury BMW car in 2017 with Faridabad registration having RC validity of 15 years till 2027. If, at the time of purchase, had the validity been registered as 10 years, I would not have bought the car. As such these cars are not pollutant generating and smoke density tested on 17/03/2022 is 0.31 against acceptable limit of 1.62. Private cars do not run as much as commercial vehicles. As such for 2 years during lockdown/ Covid, cars did not run much. As long as exhaust emitted from such cars are within the acceptable limits, they should be allowed to ply in Delhi-NCR for 15 years like in other states. After 15 years, based on fitness certification the validity may be considered for extension of validity for additional 5 years (20 years from the date of registration), as approved in several other states. Senior Citizen Owners of 10 year old diesel cars should definitely be allowed to retain their car, since they would be sparingly using the car