- India's five-year plans were a series of socio- economic development plans implemented by the Planning Commission of India. - The First Five Year Plan (1951-1956) focused primarily on agriculture and irrigation and was based on the Harrod- Domar Model. - The Second Five Year Plan (1956-1961) aimed at rapid industrialization, particularly the development of heavy industries. - This plan was conceptualized by Professor P.C. Mahalanobis and is known as the Mahalanobis Model. - The model emphasized investment in capital goods industries to achieve long-term economic growth.