The frequency and intensity of fog episodes during the winter season has been increasing during the past decade over the mega city of Delhi due to the high pollution load. The role of atmospheric aerosols is very important in the life cycle of fog in the urban areas. This paper presents the results on variation of aerosol optical properties (scattering and absorption coefficients) and black carbon (BC) mass concentration during the foggy period in winter season (December 2015 to February 2016) at the Indira Gandhi International (IGI) Airport, New Delhi. The interaction between scattering and absorbing aerosols and fog before, during and after the foggy period has been studied for a typical case. BC mass concentration along with aerosol scattering and absorption coefficients showed enhancement before and during the initial phase of dense foggy period. However, there was a steep decrease in them after the sustenance of dense fog which infers towards their possible scavenging by fog droplets. Also, it was observed that the decrease in ambient temperature and depression temperature (DT); and increase in relative humidity (RH) played a major role in sustenance of dense fog inspite of reduction in aerosol load. Single scattering albedo (SSA) showed decrease during dense fog due to comparatively more reduction in scattering aerosols than absorbing type. Both scattering and absorption coefficients showed significant correlation with cloud condensation nuclei (CCN).