The Ministry of Road Transport and Highways (MoRTH) has urged states to ensure that vehicles comply with its earlier notification and the Supreme Court's directive of having colour-coded stickers that indicate the vehicle's fuel type. MoRTH recently issued a notification to that effect.

According to the directive, diesel vehicles will bear a hologram sticker with an orange-coloured background, while cars running on petrol and CNG shall use a sticker with a light blue background. For all other vehicles, the background will be grey.

The hologram sticker is essentially a third registration plate affixed on the bottom-left side of the windshield, on the inside. It will bear details such as the registration number, the registering authority, a laser-branded PIN, and engine and chassis numbers.

In an exclusive interview to Autocar India, Priyank Bharti, Jt. Secretary, Ministry of Road Transport and Highways, Government of India said, "In India, you’ll find every kind of vehicle. There are pre-BS-III vehicles, BS-IV and now BS-VI are also available. On top of this you have multiple fuel types – petrol, diesel, CNG, ethanol, methanol and electric. So the sticker system is useful to structure the vehicle types."

Interestingly, he said that the government has got a request for cleaner BS VI vehicles to be identified separately with the use of different colored stickers. "We will most likely come out with something for a BS-VI vehicle as well," Bharti said.

Last year, the Supreme Court had instructed the Indian government to start issuing colour-coded holograms/stickers to all vehicles. One of the ideas behind this move is to restrict more polluting vehicles in an area that has already been deemed heavily polluted, either on a temporary or a permanent basis. This process was to be first implemented in Delhi-NCR starting October 2018.