This document discusses different approaches that have been used to define and measure poverty in India over time. It outlines the key concepts of absolute and relative poverty and perspectives of poverty including income, basic needs, and capabilities. It then summarizes the major expert committees that have established India's official poverty lines since 1962, including their methodology and recommendations. The most recent expert group in 2012 under Rangarajan proposed monthly expenditure poverty lines of Rs. 972 in rural areas and Rs. 1407 in urban areas based on a modified mixed reference period and normative levels of nutrition plus other necessary expenditures.