Question

people usually keep angethi /Burning coal in their closed rooms during winter season why is it advised to keep the door open

Answer 1

Because it contains polluted smokes. Corbon di oxide ,corbon mono oxide, Ammonia and many other gases which influences our health We get suffocated. And feels problem in beathing. It influence our lungs too. We started coughing.
Hope it will help you

Answer 2

The burning coal angithis will generate heat which leads to smoke.

If a person inhales this smoke for a longer period he will start experiencing breathing problem which may lead to the death of a person.

So the burning coal is never kept in a closed room.

Burning coal can create some harmful gases and it can produce some amount of toxin too. So it is better to avoid such experiment in closed areas