1.All newly diagnosed patients of Interstitial lung disease satisfying the inclusion criteria will be enrolled in the study after obtaining written informed consent.

2. Healthy individuals from community will be enrolled in the study after obtaining written informed consent.

3. Demographic details, and anthropometric data of cases with ILD and healthy individuals will be recorded on a predesigned proforma.

4. Clinical data, Forced Vital Capacity from Spirometry, Total lung capacity from body plethysmography and six-minute walk distance from six minute walk test of cases with ILD will be noted.

5.Enrolled participants will undergo Forced oscillometry

according to the current European Respiratory Society guidelines.5 Forced Oscillometry device will be preformed using Tremoflo C100 airway oscillometry system, Thorasys,Montreal,Quebec,Canada,in accordance with the recent ERS

guidelines.

I. After explaining the technique, the participant will be allowed to breathe normally into the system.

II. A minimum of three tests, each of 30 s duration, will be performed for each participant.

III. Participants will be seated comfortably throughout, holding their heads in a neutral position and wear nose clips.

IV. The participant will be asked to place their hands firmly on their cheeks to minimize the shunt effect of the upper airways.

V. Participants will be instructed to keep their mouth tightly sealed around the mouthpiece and to keep their tongue low in the mouth by tucking it under the mouthpiece.

VI. They will also be asked to avoid swallowing or talking.. Participants will be encouraged quietly throughout each test, to reassure them and to ensure as much freedom from technical errors as possible.