Due to this, it is very rare that a vehicle is not re-registered after 15 years period for which the road tax is paid," an automobile industry expert on conditions of anonymity said.. "The government has not fixed any age for the road worthiness of a vehicle in the Motor Vehicles Act, which can only be done by the Centre and not by any state government. Apart from the unavailability of space, the law enforcement agencies also face a huge task of keeping the violators in check. "It could be either done by fixing a time frame like in Paris, which has decided to phase out diesel vehicles manufactured before 2011 by 2020. Measures such as no-emission zones in European countries, which restrict the movement of Euro 1 or Euro 2 vehicles, can also be looked at.

The National Green Tribunal in its July 20 order had asked the transport department to immediately de-register diesel vehicles that are over 15 years old and those that comply with the BS-I and BS-II emission standards. Once these centres are set-up, the scrappage centres will automatically come up, which can then recycle these vehicles. The government will also have to regulate the scrappage and ending of life of a vehicle, where the manufacturers will have to ensure that a vehicle is recycled to its maximum," she added. Once de-registered, it will be illegal for these vehicles to ply on the city roads and the violating vehicles will be impounded. "It should first be ordered to set-up inspection and certification centres to device the road worthiness of a vehicle. Ironically, this will defeat the very purpose of the ban on old vehicles to reduce emissions in the city," he added.Anumita Roychowdhury, executive director at the Delhi-based environment think tank Centre for Science and Environment, suggested that the government can turn to the best practices adopted across the world in phasing out vehicles.