Lakhmir Singh Science Class 8 Solutions For Chapter 5 Coal And ... BYJU'S
(c) The slow process of conversion of dead vegetation into coal is called carbonisation. (d) The process of separation of different constituents from petroleum is refining. (e) The least polluting fuel for vehicles is CNG (f) The burning of fossil fuels causes air pollution and also causes global warming. Short Answer Type Questions. 24.