A passive cooling system for an atrium of a building by using solar-assisted natural ventilation comprising a double skin wall, plurality of glazed walls provided for plurality of adjacent spaces of the atrium, a glazed roof of the atrium and a stack flue provided on top of the atrium. Each of the plurality of glazed walls is having an outlet duct placed at a top end of the plurality of glazed walls. The double skin wall is installed on the plurality of glazed walls to complement function of the outlet duct. The double skin wall is coupled with the outlet duct. Further, the outlet duct is having a horizontal shading device and a vertical component.