What are the engine options available for MS Celerio? Is the car available with CNG option as well? If I am not wrong, the car isn't available in diesel right?
On another note, what are the benefits of having the CNG engine over Petrol.
Adding to what @Klutch said, I would say that CNG engines are more eco-friendly than petrol or diesel engines. The emissions from CNG engines are not as harmful as diesel and petrol ones. The engine stays cleaner because of CNG as the deposits from combustion are also less.
Thus, CNG engines are not only good for the environment but it promotes longer engine life as well.