The world's largest and most s ensitive cosmic ray monitor, GRAPES-3 Muon telescope located at Tata Institute of Fundamental Research's Cosmic Ray Laborotory in Ooty in Tamil Nadu recorded a burst of galactic cosmic rays of about 20 GeV (Gigaelectron volt, 1GeV= 10^9 eV) on 22 June 2015 which lasts for two hours. The burst occurred when a giant cloud of plasma ejected from the solar corona and moved with a speed of about 2.5 million kilometres per hour struck earth, caused a severe compression of earth's magnetosphere from 11 to 4 times the radius of earth, causing a severe geomagneting storm that generated Aurora Borealis and radio signal blackouts in many high latitudes countries like Norway, Greenland, Northern Canada, Siberia, Arctic Ocean. Earth's magnetosphere extends over a radius of million kilometres, which acts as the first line of defence against harmful solar and galactic cosmic rays -protecting life on earth from these high intensity energetic radiations.