Octane number is nothing but a standard gauge of the performance of the engine. If the octane number is higher, then the fuel can withstand more compression finally before igniting or detonating and vice-a-versa. In short term to say, the fuel with higher octane numbers are used in high performance vehicles powered by the petrol engines for which it need higher compression ratio. The fuel that has lower octane numbers is mostly used in the diesel engine, as a diesel engine does not utilize the fuel along with air for compression. Instead, diesel engines compress air first then infuse the fuel in the air that is heated by the compression. In India, most of the vehicles use the regular standard octane number gasoline that is between 87 and 91. The engines of Indian vehicles are specially designed as per the octane number of fuel sold here. Using the proportional octane number fuel is very important or else it will start to cause severe to the engine from inside on slow rate. The octane number displayed for the fuel sold on the fuel pumps in India based on the average of Motor Octane Number (MON) and Research Octane Number (RON). The ratio of both is also known as Anti-Knock Index (AKI). The regular gasoline sold in Indian is of octane rating 91 RON. The other premium gasoline’s are normally ordinary fuel but with the additives which do not changes any value of octane number. Now people Indian that are using imported bikes and car can also purchase the other gasoline variants that are Speed 93 and speed 97 with the RON value of 93 and 97 respectively. The engine used in Indian vehicles have lower compression ratio of 10:1 that allows them to utilize low octane number fuel without engine knocking.