New Delhi: Sixteen years after the last census in 2011, the government on Monday issued a notification for conducting India's 16th census which will include caste enumeration in 2027.

The census will be carried out with a reference date of October 1, 2026 in the snow-bound areas like Ladakh and March 1, 2027 in the rest of the country, the notification said.

"The reference date for the said census shall be 00.00 hours of the 1st day of March, 2027, except for the Union territory of Ladakh and snow-bound non-synchronous areas of the Union territory of Jammu and Kashmir and the States of Himachal Pradesh and Uttarakhand," it said.

In respect of Ladakh and snow-bound non-synchronous areas of the Union Territory (UT) of Jammu and Kashmir and the states of Himachal Pradesh and Uttarakhand, the reference date shall be 00:00 hours of the first day of October, 2026, it said.

The massive exercise, which is expected to cost the government over Rs 13,000 crore to give population-related data from across the country, will be conducted by about 34 lakh enumerators and supervisors and around 1.3 lakh census functionaries armed with digital devices.

Union Home Minister Amit Shah reviewed the preparation for the census with Union Home Secretary Govind Mohan, Registrar General and Census Commissioner of India Mritunjay Kumar Narayan, and other senior officials here on Sunday.

This is the 16th census since the exercise started and the eighth after Independence, a government statement said.

According to Article 246 of the Constitution, the census is a subject listed at 69 in the Union List in the Seventh Schedule. The census is the primary source of data collection from every section of the society and a decennial activity.

In the upcoming census, caste enumeration will also be done, the first such exercise since Independence. The last comprehensive caste-based count was done by the Britishers between 1881 and 1931. Caste was excluded from all census operations conducted since Independence.

The decision to include caste enumeration in the upcoming census was taken by the Cabinet Committee on Political Affairs chaired by Prime Minister Narendra Modi on April 30.

"Considering all these circumstances, and to ensure that our social fabric does not come under political pressure, it has been decided that caste enumeration should be included in the main census instead of being conducted as a separate survey," an official statement had said.

In 2010, then prime minister Manmohan Singh had assured the Lok Sabha that the matter of caste census would be considered in the cabinet. A group of ministers was formed to deliberate on this subject and majority of the political parties recommended conducting a caste census.

However, the previous Congress-led government opted for a survey instead of a caste census, known as the Socio-Economic and Caste Census (SECC).

The SECC conducted in 2011 under the UPA government did collect caste data but it was never fully published or utilised. Bihar and Telangana have conducted caste surveys in the last three years.

While some states have conducted surveys to enumerate castes, these surveys have varied in transparency and intent, with some conducted purely from a "political angle, creating doubts in society", the government had said.

In the upcoming exercise, the provision of self-enumeration will also be made available to the people.

The two-phased census will start with the first step of house-listing operation (HLO) in which the housing conditions, assets and amenities of each household will be collected. This will be followed by the second phase of population enumeration in which the demographic, socio-economic, cultural and other details of every person in each household will be gathered.

Very stringent data security measures would be kept in place to ensure data security at the time of collection, transmission and storage.