Petrol commercially available in INDIA for Indian passenger cars has octane number in the range: A 40 to 50 B 60 to 70 C 80 to 85 D 95 to 100

80-85 is the octane number for petrol fuel in India.

For Diesel, its40-45.

Thanks Mr. Mitra.

I thought  C 80 to85

According to experts, 

 There are2 types of Fuels sold in India - Regular and Premium.

There are only2 differences between Premium and Regular Fuel :

- Higher Octane Ratings in Premium Fuel

- Some Additives and booster used in Premium Fuel which claims to make it refined

Higher Octane leads to higher combustion and energy transformed. Its general rule that burning fuel with a lower octane rating than recommended octane rating of the car, deteriorates the efficiency and power output of the Engine.

Also, to be noted that Burning Fuel with higher Octane ratings does not produce any additional power or efficiency of the engine and there is no benefit as such.

 Recommended Octane Rating of Cars in India

In India, the Octane Ratings recommended by the most of the manufacturer Car Models are in range of87 -90 Octane which is available as regular fuel in India . High End Engines, V6, Turbo Jet Engine and Sports Car requires higher combustion and can produce efficiency with high Octanes. The Octane level in Premium Fuel can vary from93 -97 Octane.

India's economy-class vehicles usually have compression ratios under10:1, thus enabling them to use lower-octane petrol without engine knocking.

Usually it is87.

I have not been in India, so I only can guess C80-85; 

The US and EU standards are much higher87-91 depending on the model and manufacturer of the car