Anil K. Narendran, J.

These writ appeals arise out of the common judgment of the learned single Judge dated 08.12.2016 in W.P.(C)No.18028 of 2016 and connected cases.

2. The appellants in W.A. Nos. 7, 49, 50 and 54 of 2017 (arising out of W.P. (C) Nos. 26433, 20015, 25629 and 25646 of 2016 respectively) are the manufacturers/authorised dealers of commercial passenger/goods vehicles under different categories as specified under the Motor Vehicles Act, 1988 and the Central Motor Vehicles Rules, 1989. The appellants in W.A. Nos. 2511, 2512, 2513 and 2515 of 2016 (arising out of W.P.(C) Nos. 40105, 40248, 40119 and 40252 of 2016 respectively) are persons who purchased Heavy Passenger Motor Vehicle chassis fitted with diesel engines meeting the Mass Emission Standards 'Bharat Stage III' (for brevity 'BS III') for the purpose of stage carriage/contract carriage operations after body building. As per the sale certificate/tax invoice produced along with the writ petitions, they purchased chassis fitted with diesel engine meeting 'BS III' mass emission standards on 22.11.2016, 31.10.2016, 24.11.2016 and 31.10.2016 respectively.

3. By virtue of Ext.P1 notification, i.e., G.S.R.643(E) dated 19.8.2015, the Mass Emission Standards 'Bharat Stage IV' (for brevity 'BS IV'), as contemplated under sub-rule (15) of Rule 115 of the Central Motor Vehicles Rules 1989, has been implemented in various districts, States and Union Territories, including State of Kerala, in respect of four wheeled vehicles manufactured on and after 1.4.2016, except the four wheeled transport vehicles plying on Inter-State Permits or National Permit or All India Tourist Permits, within the jurisdiction of the said districts, States and Union Territories.

4. According to the appellants, by Ext.P1 notification, 'BS IV' standards have been implemented only for four-wheeled vehicles and have no application to vehicles having more than four wheels, i.e., six wheeled vehicles/chassis manufactured/purchased by the appellants after 1.4.2016, which are fitted with diesel engine meeting only 'BS III' emission standards.

5. On 22.3.2016, the 2nd respondent Transport Commissioner issued Ext.P2 circular specifying that the Mass Emission Standards 'BS IV' shall be applicable in the State of Kerala in respect of four wheeled vehicles manufactured on and from 1.4.2016, except the four wheeled transport vehicles plying on Inter-State Permits or National Permits or All India Tourist Permits, within the jurisdiction of the State. Later, the 2nd respondent issued Ext.P3 communication dated 29.4.2016 to all Deputy Transport Commissioners, Regional Transport Officers, etc., stating that 'BS IV' norms are applicable to vehicles manufactured on or after 1.4.2016 and having four or more than four wheels. Still later, the 2nd respondent issued Ext.P4 circular dated 23.5.2016, according sanction to register 'BS III' vehicles manufactured by M/s. Daimler India Commercial Vehicles Pvt. Ltd. and M/s. VE Commercial Vehicles, for a period of three months from the date of the circular, on public interest, on condition that no further exemption will be granted at any event.

6. Challenging Ext.P3 communication of the 2nd respondent, one of the manufacturers (M/s. Autobahn Trucking) approached this Court in W.P.(C)No.18028 of 2016 and obtained an interim order dated 6.6.2016 staying the operation of Ext.P3. Thereafter, the 2nd respondent has clarified in Ext.P5 communication dated 17.6.2016 that 'BS IV' specifications are applicable only for vehicles having four wheels.

7. In W.P.(C)No.18028 of 2016 and other writ petitions filed by the manufacturers, Ext.P3 communication dated 29.4.2016 of the 2nd respondent was under challenge, contending that by Ext.P1 notification 'BS IV' standards have been implemented only for four-wheeled vehicles. In the writ petitions filed by those who purchased six wheeled vehicles/chassis manufactured after 1.4.2016, which are fitted with diesel engine meeting only 'BS III'