<br/>The Prime Minister Dr Manmohan Singh has said, census data will help the Government plan its development work. Terming the census data as a treasure house of information, the Prime Minister who was enumerated for the Census in the national capital requested each citizen to participate in the national endeavour and ensure that every person is included in the exercise. Dr Singh said the Census of India is the most massive operation for compiling statistics anywhere in the world.<br/><br/>He said, some of this data forms an important base for planning the level of our economic and social activities and it constitutes an important input in the processes of planning and development.<br/><br/>The biggest Census exercise ever to be attempted in history to cover India's 1.2 billion population began on April one with President Pratibha Devisingh Patil being the first to be enumerated in the decennial exercise. The 15th National Census, which will see over 25 lakh officials capturing the socio-economic-cultural profile of its citizens, will also seek information for the creation of the National Population Register.