Selection intensity of human populations has been extensively studied. But, effect of environmental exposure on selection intensity is yet to be studied. Thus, an attempt has been made to investigate the selection intensity of two Santal groups having similar socioeconomic and geo-climatic condition but exposed to different environmental condition of Birbhum district, West Bengal. Data on fertility and mortality have been collected with the help of a well tested questionnaire/schedule from total 138 (affected group = 82, control group = 56) evermarried post-reproductive (i.e. age =45 years) women. Here, women of affected group were exposed to stone dust, noise and other environmental hazards as due to their settlement and occupation in the stone quarries and crushers. On the other, individuals of control group were free from those exposures as they were living far away from stone quarries and crushers and engaged in household work and agricultural activities. Both Crow’s (1958) as well as Johnston and Kensinger’s (1971) indices were applied for calculating selection intensity. Exposure to stone dusts, noise and other environmental hazards has markedly influenced the selection intensity and some selected demographic events in affected group. Selection intensity index was low in affected group compared to control group. That indicates individuals of affected group are less selected to their respective environment than individuals of control group, which is relatively free from all those hazards.