Many genuine names have been left out and many bogus names are registered, a highly placed source in the Home Ministry said.
The Home Ministry has laid down the modalities for Foreigners' Tribunals in Assam to deciding appeals made by people not satisfied with the outcome of claims and objections filed against the NRC.
The Ministry had in May issued an order mandating the Foreigners' Tribunals in Assam to deliver verdict of any case related to those people whose names could be excluded from the final list of NRC within four months, said the source.
"The government's intention is to ensure no illegal immigrant is registered under the NRC. Foreigner tribunals are handling issues to curb illegal stay of foreigners in India," said the source, privy to the development.
In the draft lists published in July 2018 and June this year, around 41 lakh people have been excluded. Around 36 lakh people have filed claims against their exclusion and objections have been filed against two lakh inclusions.
The hearings for these claims and objections are underway at various NRC centres.
All those identified as illegal immigrants under this process will have to be deported, as per the resolve of the government.
The government on Friday told the Supreme Court that India "cannot afford to become the refugee capital in the world", as it sought more time to re-verify the inclusions and exclusions in the NRC draft list.
The NRC, first published in Assam in 1951, is being updated as per directions of the Supreme Court to segregate Indian citizens living in Assam from those who have illegally entered the state from Bangladesh after March 25, 1971.
There was a major uproar earlier as a decorated former Indian Army officer Mohammad Sanaullah, was among those excluded from the draft NRC list.
The 52-year-old army veteran was sent to a detention camp. He was granted bail by the Guwahati High Court on June 7.
While the government has resolved to deport all the illegal immigrants identified under the NRC exercise, it will have to be seen how lakhs of people can be sent to Bangladesh, which has always maintained that none of its citizens have moved to India illegally.
In all probability, they will first be lodged in detention camps within Assam.
After the first draft NRC list was published, the then Home Minister Rajnath Singh had visited Dhaka to brief his counterpart on the contours of the exercise.
( With inputs from IANS )