Air pollution over megacity New Delhi has gained significant attention in the recent times. Local pollution along with advection from upwind sources, long range transport and also festivities (e.g., Diwali) involving large emissions due to burning of fire crackers all lead to high loading conditions over the city. In this study, we carry out an assessment of particulate pollutant event that coincided with the festival of Diwali during 2016 using multiple parameters related to particulate pollution from ground and satellite based measurements in relation to the observed climatology during the period 2000 to 2016. Our analysis reveals that 2016 severe air pollution episode was exacerbated by the long range transport of fine absorbing aerosols emanating from biomass/stubble burning in the adjacent states to the Northwest. Our study based on concentration weighted trajectory (CWT) analysis using PM2.5 mass concentration and AOD shows that the high loading conditions were related to trajectories that pass through North-West of NCT. During 2016, the period after Diwali also coincided with air mass traversing over large biomass burning areas. Our analysis on long term changes to the fire counts reveals that these events are increasing at an alarming rate of ~25% per year since 2000 with potential for high particulate pollution over downwind cities such as Delhi.