Background: Globally, the most important risk factor for chronic lung diseases is smoking of tobacco. Cigarette smoke, passive smoking, biomass smoke and infectious organisms may activate alveolar macrophages, bronchial epithelial cells and other cellular elements in the airways of genetically susceptible individuals leading to the development of chronic lung diseases. But, unfortunately, a first diagnosis of such disease is established in smokers and/or exposed to other smoke exposures only at a later stage after being exposed for several decades. However, before reaching this clinical stage, lot of structural and functional changes in the respiratory tract do occur deteriorating respiratory defence mechanisms leading to appearance of symptoms, worsening of quality of life and ultimately death. Early diagnosis of such impairment may have important stimuli to either quit smoking or to participate in smoke intervention programmes. With this background, this study was conducted to evaluate the nasal mucociliary clearance (mirror image of bronchial clearance/biomarker of nasal mucosal function) of subjects exposed to tobacco smoke, cook smoke and to compare with that of the healthy volunteers unexposed to such smoke. Materials & Methods: NMC was measured in 25 smokers, 25 non smokers ,50 biomass fuel users and in 50 clean fuel users of age group ranging from 18 – 45 years who had no medications and no systemic illness. The time elapsing until the first experience of sweet taste at posterior nasopharynx, following the placement of saccharin particle approximately 1cm behind the anterior end of inferior turbinate was recorded as NMC clearance time. Results: Mean NMC of the smokers (481.2 ± 29.8 secs) was significantly higher than that of non smokers (300.32 ± 17.4 secs), (p<0.01). NMC was found to be increasing as the duration of smoking increased. (NMC in smoking <1 year =492.25 ± 79.93 secs, NMC in smoking for 1 – 5 years = 516.7 ± 34.01 secs, > 5 years = 637.5 ± 28.49 secs). NMC was also significantly (p =0.02) prolonged in biomass fuel users (604.97 ± 220.42 secs) in comparison to clean fuel users (455.12 ± 161.76 secs). Prolonged clearance observed in smokers and biomass fuel users may be due to the toxic effects of the components of smoke. Conclusion: NMC measurement is a simple, inexpensive, non-invasive, screening test which can be used as an early diagnostic tool for respiratory diseases caused by exposure to air pollutants such as cook smoke and tobacco smoke. Our study impresses upon the important role of NMC in the health of sinonasal cavities and the need for initiating smoking cessation programs and efforts to promote cleaner fuels, improved stoves, better home ventilation which in turn may promote the lung health of the general population.