people burn fuel to obtain the energy fro,m it which is use for differnt purpose like running vehicle, cooking foods etc
no its not necessary to burn them
this burning of fuel can cause diifernt bad effect like pollution ,and green house effect , global warming etc
we can find different methods to obtain energy
like we can use solar energy, wind energy to run vehicles and solar cooker to cook food etc
this using renwweable energy(wind solar etc) instead of this non renewable energy (fuesl like pertol diesel etc)can prevent the pollution caused