I have been tracking this company for some time now and think it has real competitive advantages both over other forms of fuels and other companies.
Here is an extract from the Q2FY18 concall about their pricing formula: (if you think about it, they are always at a price advantage, no matter the input cost increase!)
I will be closely tracking their bidding aggressiveness for other cities, Raigad expansion progress. Lots of opportunity in this scrip from the long term. Their moat will not extinguish unless we enter into the age of electric mobility which is at least 10 years away. Also, as noted by the management too, electric vehicles will displace the more polluting fuels first and only then CNG.