Question

in a closed room if there is some material that is burning you may have felt suffocation why ?

Answer 1

Because when something burns, it uses oxygen that's why suffocating we feel

Answer 2

In a closed room, the amount of oxygen is limited and if some material is burning then if would use oxygen for combustion and also realease harmful pollutant ( if it is a solid or liquid). Thus, oxygen is low and other pollutants more, making the room suffocated