Half a million people die every year due to COPD in India, about over 4 times the number in USA & Europe. Asthma is one of the most common chronic diseases worldwide with an estimated 300 million affected individuals. The subjects recruited directly from the department of pulmonary medicine based on the inclusion and exclusion criteria. Minimum 60 subjects needed for the study. The parameters of lung volumes (SVC, FVC, FEV1, FEV1/FVC%, FEV1/SVC%) recorded by ATS standardized MEDISOFT® spirometry. FEV1/SVC diagnosed obstruction in 36 out of 38 patients (94.74%) compared to FEV1/FVC which diagnosed obstruction in 27 out of 38 patients (71.05%) with statistical significance (p= 0.009). The discrepancy is 23.69%.