Thousands of officials have started the long-drawn process of mapping cities, towns and villages that is likely to throw up new information on the changing demographic profile in the country.

Millions of volunteers and census officials will visit every household around the country in the next few years to gather information on jobs, education and quality of life.

India's population is projected to grow to 1.19 billion in 2011 from 1.13 billion in 2008, according to census authorities.

More than a decade of reform programmes is estimated to have pushed India's long-term economic growth rate to around 8.7 percent this fiscal year. But India urgently requires more infrastructure and creation of new jobs.

India produces 2.5 million graduates every year, but only about 15 percent are suitable for jobs in technology and outsourcing, home ministry officials say. Millions still live in acute poverty.

"The census will be a review of trends of the high growth rate economy and it is going to be the report card on how the population has responded to it," Abheek Barua, chief economist at the HDFC Bank said.

India's last census in 2001 revealed an increasing demographic divide between poorer states in the north and the economically better-off south.

Experts say the imbalances have fanned political tensions, with Hindu hardline groups in India's financial capital of Mumbai threatening poorer migrant labourers from north India.

"The census will tell us the patterns of migration and where is the emergence of the young urban population taking place," Barua says.

Unlike China, which has an ageing population, the result of the country's one-child policy, half of India's population according to the 2001 census was younger than 25 years.

"It is an advantage to India and this census will provide vital information about the young population and where exactly is all the so-called development heading," Bikram Sen, a former census director, said.