Particulate Matter Index (PMI), as estimated on John Payne tar predictor, offers a simple, quicker and reliable relative evaluation of predicted tar yields from cigarettes made from different tobacco genotypes. One of the promising approaches for developing low tar/low nicotine smoking products is to breed varieties which have inherently low tar/low nicotine yield potential. Though this seemed a remote possibility hitherto, the present-day Indian bright tobacco cultivars are showing a variability of 27 per cent (132-182 mg/g of PMI). Monitoring of 9 cytoplasmic male sterile lines (CMS) developed under N. undulata background showed PMI variability in the range 18.5-183.2 mg/g. The largest difference was observed in the yellow special cultivar between fertile and its CMS counterpart (175.5 and 148.5 mg/g). The advance breeding lines also showed PMI variability in the range 161-212 mg/g. An investigation designed to exploit mammoth genes for improving yield and quality of bright tobacco indicated that all the 9 mammoth lines exhibited lower PMI (138.7-178.7 mg/g) than the standard cultivar, Hema (183.7 mg/g). Assessment of the germplasm accessions maintained at this Institute also showed wide PMI variability offering promising possibility for developing low tar/low nicotine varieties, notwithstanding the recognised fact of environmental factors and seasonal effects greatly influencing the leaf chemistry and consequently the smoke characteristics.