Vehicles travelling from outside Himachal Pradesh and not bearing Himachal Pradesh license plate need National Green Tribunal (NGT) permit to visit Rohtang pass. It is to be noted that only limited vehicles are permitted to Rohtang Pass on a daily basis. Hence, it is advisable that you book your trip in advance, as permits are limited and are issued online on a first-come-first-serve basis. Tour operators and Himachal tour package providers usually book permits for visitors. Rohtang Pass remains closed on Tuesdays on account of maintenance purposes.