India began work today on the country's 2011 census, which has been described by a government minister as 'the biggest exercise since humankind came into existence'.
More than 2.5m enumerators will take part in the operation aimed at quantifying the country's 1bn plus population.
For the first time, officials will also have to collect fingerprints and photograph every Indian resident for the register.
The exercise has formidable challenges including coverage of a vast geographical area, widespread illiteracy, and people with a diversity of cultures, languages and customs.
'The census is a means of evaluating once in every ten years, in a dispassionate manner, whether government programmes are reaching their intended target and plan for the future,' Census Commissioner C Chandramouli said.
'It is also a challenge to see that the 2.5m enumerators carry out the instructions we have given them without error,' Mr Chandramouli said from his New Delhi office.
The twin census and population register processes will stretch over 11 months, consume 11.63 million tonnes of paper and will cost €900m.
'India has been conducting national census since 1872,' said Mr Chandramouli. 'Nothing - floods, droughts, even wars - has been able to stop it.'
The census started with officials visiting Indian President Pratibha Patil for her signature during the first leg of the process called house-listing.
