The present study is carried out to explain the presence of large concentrations of SO2 in atmosphere of Pakistan during June, 2011. Large volcanic eruptions are a major source of greenhouse and trace gases. The eruption of Mount Nabro in June, 2011 injected large amount of SO2 into stratosphere. Nabro volcanic eruption generated a layer of sulfate aerosols, which resided in stratosphere for months. The total amount of SO2 that was injected into the atmosphere was estimated to be 1.3-2.0 Tg. Data products of Global Ozone Monitoring Experiment (GOME-2), Ozone Monitoring Instrument (OMI) and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) were used to study SO2 concentrations and plume movement over Pakistan. HYSPLIT backward trajectory model is utilized to study the origin of SO2 plume. The study confirms that SO2 plume originated from Nabro volcanic eruption and caused significant atmospheric perturbations and affected the air quality of Pakistan. SO2 emissions from volcanic eruptions can pose serious hazard to population as well as global climate.