The Indian Government implemented the project “System of Air quality Forecasting And Research (SAFAR)” for the “Commonwealth Games” 2010 in Delhi. It was adopted by the Global Urban Research Meteorology and Environment of World Meteorological Organization as its pilot project. We used data from a dense network of stations built over 2500 km2 in Delhi under the SAFAR project to investigate temporal and spatial variations of fine (PM2.5) and coarse (PM10–2.5) particles, and discuss their deposition and the airborne mass fractions that were retained after a certain amount of time. The 24-hour coarse particle (PM10–2.5) means during the Games period were always above the National Ambient Air Quality Standard NAAQS (100 μg/m3) at all the sites except the airport. In still air, initial PM10–2.5 can reach below 50 μg/m3 by deposition in an hour. The 24-hour PM2.5 means reveal that they were either around or below the NAAQS (60 μg/m3) at some sport complexes, whereas they fluctuated between 60 and 80 μg/m3 at the other sites.