New Delhi: West Bengal, whose chief minister Mamata Banerjee has kicked up a storm over the exclusion of 40 lakh people from the final draft of NRC in Assam, was the biggest defaulter in the verification process, Registrar General and Census Commissioner of India Sailesh said on Wednesday.

Sailesh, who oversaw the entire exercise of the National Register of Citizens (NRC), said he had even deputed his own staff to help the West Bengal government in collecting the documents sought by the NRC authorities but the efforts were not fruitful. The verification process was for people who belong to a different state but reside in Assam due to various reasons.

According to him, the state returned only six per cent of the documents sent to it by NRC authorities. Other big defaulters were Bihar, Chandigarh, Manipur and Meghalaya which returned just 2 to 7 per cent of the documents after verification.

The names of at least five lakh people could not be included in the final draft of the NRC because other states and central organisations failed to check and send back the results of the verification of citizenship claims made by these people, sources said

"The largest number of documents that we have not received among all states was from West Bengal. We had to struggle. We had to follow up. But we have not received substantial number of documents from West Bengal. The response (of West Bengal) in terms of results was not satisfactory," he said.

The draft NRC, a list of Assam's citizens, was published on July 30 that excluded 40 lakh residents of Assam. Most of the names were excluded due to lack of proper documents proving Indian citizenship.

Sailesh also said that there was a meeting through video conference between the officials of the West Bengal government and the NRC authorities during which a request was made to send the responses.

"West Bengal was the only state where we made an exception by deputing my own staff to assist the state government. But we have not received all required documents for the draft NRC," he said.

Asked about the number of documents that the West Bengal did not provide, Sailesh said it would be a "substantial number".

The comments bear significance as Banerjee continues to attack the BJP and the central government over the draft NRC in Assam, accusing the party of playing vote-bank politics, while also warning that the issue will "destroy" India's relationship with Bangladesh.

She said only one per cent of the 40 lakh residents, whose names are missing from the draft NRC, could be infiltrators, but people are being "harassed" in the name of being foreigners.

She has alleged that the NRC exercise in Assam was done with a "political motive" to divide people and warned that it would lead to bloodbath and a civil war in the country.