Agriculture before the Green Revolution was limited by lack of irrigation and technology, resulting in low and unpredictable crop yields. This caused global concerns about the ability to feed growing populations. After independence, India established agricultural institutions and saw some improvements but productivity remained low. The Green Revolution starting in the 1960s introduced high-yielding varieties of wheat and rice, irrigation projects, and chemical fertilizers, doubling food production in India and alleviating famine concerns. Agricultural advances after the Green Revolution continued to increase yields and crop diversification.