How steam inhalation work in sinus problems?

Increased mucociliary activity has been observed with saline irrigation and steam inhalation which seems to achieve faster recovery. In patients of chronic sinusitis disease, the mucociliary activity is known to be impaired. It is found that steam inhalation improved mucociliary activity significantly in chronic sinus patients.

Nasal inhalation of steam has been proposed as treatment of viral colds on the assumption that increased intranasal temperature will inhibit replication of rhinovirus. The steam inactivates the flu virus. Most people at home use the old fashioned way of head over a bowl of steaming hot water.
Eucalyptus oil or menthol or aromatic herbal leaves (thulasi) in steam inhalation is recommended for relieving nasal congestion and sinus congestion, usually from colds and flu. It can be done two to four times a day to relieve symptoms.

The steam therapy is good after nasal surgery to get rid of the crusts and blood clots.
Safety Precautions- Be careful in children, avoid burns and scalds.