The 2011 Census was the 15th Indian Census and the seventh since India's Independence, serving as a decennial population count conducted every ten years. It is a statutory concept and exercise, mandated by the Census Act, 1948, which provides the legal framework for its systematic conduct. The census was created to collect, compile, analyze, and disseminate demographic, social, cultural, and economic data for the entire population, which is crucial for government policy and planning. The first synchronous census was conducted in 1881, and the practice has continued every ten years since then.
The mechanism of the 2011 Census involved two phases: the House-listing and Housing Census and the Population Enumeration. The House-listing phase began on April 1, 2010, and involved collecting information on all buildings and household amenities. The Population Enumeration phase was conducted between February 9 and February 28, 2011, with the reference date being 00:00 hours of March 1, 2011. A key provision of the Census Act, 1948, is the guarantee of strict confidentiality, where individual returns are protected and cannot be used as evidence in any court proceedings, except for offenses under the Act itself.
The census connects directly to the Registrar General and Census Commissioner of India under the Ministry of Home Affairs, which is the central body responsible for its execution. The data collected is vital for the delimitation of Parliamentary and Assembly constituencies and for formulating welfare schemes and five-year plans. In the first phase of the 2011 Census, information was also collected for the National Population Register (NPR), which is used to issue a unique identification number to residents. The subsequent census, originally planned for 2021, was postponed due to the COVID-19 pandemic and is now scheduled for 2027. The upcoming 2027 Census will be India's first fully digital census, introducing a new mechanism of self-enumeration via a web portal, which is a significant change from the paper-based method of the 2011 Census.