ORDER : Permission to file Civil Appeals is granted and delay condoned in C.A. Diary No. 25131/2018. 2. In most of these cases, the private respondents who had filed the application(s) before the National Green Tribunal have been served but they have not entered appearance. 3. Heard learned counsel for the parties. 4. The National Green Tribunal vide its Order dated 24.11.2017 had issued various directions in these matters. The appellants are aggrieved only by Direction No. 7 which reads as under: "7. All the coaches/buses and other vehicles plying at the airport should be CNG and must comply with the prescribed emission standards. Non-CNG buses/coaches or other vehicles plying at the airport, should be converted to CNG within six months from today." 5. It is pointed out by the appellants herein that, apart from the coaches and buses, the National Green Tribunal has directed even "other vehicles plying at the airport should be CNG". It is pointed out that there are vary kinds of specialized vehicles which cannot be on CNG mode at all. It is also pointed out by the learned counsel for Delhi International Airport Ltd. ("DIAL") that is supposed to provide certain fire tender and various kinds of vehicles for quick reaction teams which cannot be also on CNG mode. 6. In our view, the grievance raised by the appellants seems to be justified. We, therefore, modify Direction No. 7 by removing the words "other vehicles" therefrom, meaning thereby, the direction shall be confined to coaches and buses. 7. The appeals are allowed in the aforesaid terms. 8. Pending applications, if any, stand disposed of.