Ubiquitous ‘Black carbon’ released into atmosphere as a product of fossil fuels burning and biomass have significant role in climate system by absorbing and scattering of solar radiation as well as effect human health [cardiopulmonary hospitalization (short- term effect) to chronic respiratory disease (long- term effect)] due to sub-micron size. Its total global emissions are 8 TgCyr^-1 in 2004, in which maximum contribution is from open biomass burning and fossil fuel combustion. But, shows large variation in emission estimates are due to different sources of emission. Mixing of different component like sulphates, nitrates, organics, dust and sea salt to black carbon, contribute to change in radiative forcing (changes by ~1.4-2). Apart, from warming of the troposphere and cooling of the surface, black carbon is responsible for snow melt, affects cloud cover and life time thereby affects rainfall mechanism, and reduced visibility. Also, act as site for various chemical transformations in the atmosphere, due to nature of porosity and absorption.