Punjab is known as the "Land of Five Rivers. "Punjab's major industry is agriculture. The state has a total of 23 universities, with ten being private, nine being public, one being central, and three being deemed. Indian Institute of Technology, Ropar and Indian Institute of Management Amritsar are two prestigious colleges in the state for studying engineering and MBA, respectively. The Christian Medical College, Ludhiana, which has been in operation since 1894, is one of the oldest medical colleges in the country. Punjab Agricultural University is a world-class agricultural research university. Manmohan Singh (Former Prime Minister of India) and Dr. Har Gobind Khorana (Biochemistry Nobel Laureate) are bot alumni of Panjab University, Chandigarh.