One nostril passes and the other does not pass is not normal. It may be caused by a deviated septum, or it may be caused by adenoid hypertrophy, rhinitis, and nasal polyps. 1. deviated nasal septum: one nostril is ventilated and the other is inaccessible may be due to deviated nasal septum, because when the nasal septum is deviated to one side, the other side will become narrow, which leads to poor ventilation in the nasal cavity, and this will cause nasal congestion, and sometimes lead to headache or nosebleed. 2. adenoid hypertrophy: adenoid hypertrophy may be caused by adenoiditis, rhinitis, and nasal polyps. 2. adenoid hypertrophy: adenoids are mostly seen in children, adenoids in the top of the nasopharynx, adenoids over-enlargement will naturally block the nasal cavity, the airflow can not be normal through the nostrils will appear a ventilation and a non-ventilation of the situation. 3. Rhinitis: Rhinitis can lead to swelling of the nasal mucosa and narrowing of the nasal passages, resulting in one nostril being ventilated and the other not. 4. Nasal polyps: Nasal polyps can block the nasal airway, resulting in a decrease in nasal airflow, leading to the phenomenon of one nostril ventilation and one not working. If your nostrils are not working, it is recommended that you go to the hospital for a checkup to determine the specific cause of the problem and then treat it under the guidance of your doctor.