What is the criterion for the purity of a place, and is it permissible to pray in a room that contains a small amount of impurity, but not in the place of prayer?

The fundamental principle regarding lands and places is purity. A Muslim should pray in pure places, as the earth has been made a mosque and a purifier. It is permissible to pray in a room containing impurity if this impurity does not come into contact with the worshipper's limbs or clothes. The condition is the purity of the place where the worshipper's limbs rest and where their clothes meet the ground. So, if the impurity is adjacent to the body without any part of the body or limbs touching it, that does not invalidate the prayer.