The smaller the baby’s nose is not ventilated, the more obvious the symptoms are. Because the baby’s nasal cavity is not fully developed, the volume of the nasal cavity is relatively small, in the case of inflammation, the mucous membrane is congested and edematous, the nasal passage becomes narrow, there is a narrowing there is an obstruction of the performance, there will be nasal congestion, that is, nose blockage. As he grows older and his nasal cavity develops, slowly becoming larger and gradually approaching that of an adult, this symptom will decrease with age. Adults in the case of a cold, the same will also appear blocked nasal passages, the reason is the same.