While efforts are on by European scientists to monitor the rapidly decreasing magnetic field of the Earth through satellites, Indian researchers were the first to report the ground data from the Indian Antarctic stations at Maitri in 1995, Indian Institute of Geomagnetism (IIG) sources said here today.The study was very important as many people were not aware of the fact that this magnetic field was cardinally responsible for trapping harmful solar radiations and keeping them at great distances from the Earth. This action prevents them from harming and destroying life-forms on Earth, Dr Bhattacharya said, adding that its geomagnetic field was the first line of defence.