Standard diesel fuel (sometimes called diesel oil) comes in two grades: Diesel-1 (D1) and Diesel-2 (D2). Diesel or Diesel fuel in general is any fuel used in diesel engines. That’s why it’s also commonly called as AGO or Automotive Gas Oil. Diesel fuel is a type of fuel derived from the distillation of oil that is heavier than gasoline but lighter than engine oil and heavy oil.
D1 is similar to kerosene and is lighter than D2. While D2 is sold most of the time, D1 is sold during winter in very cold climates and not sold in hot weather countries. But D2 is easily available in most countries around the world. Despite rising awareness of environmental protection, D2 remains to be a key type of fuel for use in vehicles in many countries.