By Sunita Nahar
BBC News, Calcutta
Officials in India are investigating reports a man has been repaying a debt which began with a loan of 40kg of rice with nearly 30 years of bonded labour.
Authorities in eastern Bihar state said that it was a rare case and that the landlord would be prosecuted.
But Anti-Slavery International says such practice is widespread in India.
It says that although bonded labour was outlawed in India in 1976, millions of men, women and children are enslaved by the system.
Jawahar Manjhi, a farm labourer, lives in the Indian village of Paipura Barki with his wife and four sons.
Twenty-seven years ago, he took 40kg of rice on loan from a local landowner for a family wedding and in exchange it was agreed he would work in the lender's field - one day of work for 1kg of rice - to pay off his debt.
But since then he has taken out more loans of rice and does not know exactly how much he has paid back.
Jawahar says he was told he would be freed if he paid more than $100 (£51), but that is an amount far beyond his reach.
The landowner was contacted but was not available.
The district's magistrate, BB Rajendra, said he was looking into the case and, if true, action would be taken.
Beth Herzfeld of Anti-Slavery International said she welcomed his assurance.
But she said that even though bonded labour has been illegal in India for 30 years, there have been few prosecutions and no convictions so far against those who use it.