No document will be collected from anyone during the exercise to be carried out to update the National Population Register, Union minister Nityanand Rai said on Wednesday.
"No document is to be collected during the updation of NPR 2020," Rai, the Union Minister of State for Home, said replying to a written question.
The NPR data will be collected along with the house-listing phase of the census to be conducted from April 1 to September 30.
Punjab, Kerala, West Bengal, Rajasthan, Madhya Pradesh, Chhattisgarh are some of the non-BJP ruled states which have apprehensions about the NPR and are critical towards the exercise.
The objective of updating the NPR is to create a comprehensive identity database of every usual resident in the country. The database would contain demographic and biometric particulars.
The notification for the house-listing phase of census and NPR exercise came recently amid furore over the contentious Citizenship Amendment Act (CAA).
The data for NPR was last collected in 2010 along with the house-listing phase of Census 2011. Updation of this data was done in 2015 by conducting door-to-door surveys.
While updating the register in 2015, the government asked details like Aadhaar and mobile numbers.
This time, information related to driving licence and voter ID card may also be gathered, officials said, adding that PAN card details will not be collected as part of this exercise. Questions related to place of parents' birth are voluntary to answer, the government had said.
For NPR, a usual resident is defined as a person who has resided in a local area for the past six months or more, or a person who intends to reside in that area for the next six months.
The law compulsorily seeks to register every citizen of India and issue a national identity card.