India is set to build the world’s largest magnet, which will be four times larger than the 12,500-tonne magnet housed in the Compact Moon Solenoid (CMS) detector at CERN (European Organization for Nuclear Research) in Geneva. The CERN-like underground detector for the India-based Neutrino Observatory (NO) will be housed in Theni near Madurai. A 2-km underground tunnel is under construction at a cost of $250 million.