Which preventive measure is most effective against air-borne diseases?
Wearing masks and covering the mouth while sneezing help prevent the spread of air-borne diseases like pneumonia and common cold. This follows from NCERT principle where relation explains outcome clearly for students.
Ref: NCERT Biology Textbook for Class XI and XII (Zoology section), Chapter: Biology - Zoology portion covering relevant system and function, Topic: Structural organization and physiology.