At least 70,000 children, mainly from Bangladesh and Nepal, are working in hazardous and inhumane conditions in mines in the Jaintia Hills area of the Christian-majority state of Meghalaya in northeastern India.
An international human rights group and an Indian NGO have urged national and international bodies to investigate.
India has many mechanisms to address child labor but they are ineffective in the Jaintia Hills of Meghalaya, Kazuko Ito, secretary general of Human Rights Now (HRN), a Tokyo-based international human rights group.
Meghalaya comprises three hills districts - Garo, Jaintia and Khasi.
An HRN team collaborated with the Impulse NGO Network, a Meghalaya-based NGO, to study the child labor situation in the Jaintia Hills from May 31-June 2. The team visited three coal mines and interviewed 45 people, including child workers.
Ito said they found most children below 14. A 12-year-old boy told them he has worked there since he was eight.
The children also work in extreme danger with few safety measures. They cut coal in deep underground holes with little air supply.
Ito said her team felt suffocated and made a hasty retreat after going some 1000 meters into a coalmine hole.
The team quoted some elders as saying middlemen duped the children promising easy money for simple tasks.
Hasina Kharbhih of the Impulse NGO Network alleged that the mine owners are also guilty of extrajudicial killings as they lock up children in closed mines as punishment and many die.
She said her group has worked in the Hills for the past five years and had reported the matter to the federal Social Welfare Department and National Human Rights Commission, but so far no action has been taken.
The NGOs want international monitoring bodies such as Commission of Inquiry of ILO and UN Special Rapportuers to look into child trafficking and extrajudicial killings in the Jaintia Hills.
They also want the Indian government to sign a bilateral agreement with Nepal and Bangladesh to prevent child trafficking and prosecute offenders.
The groups also want international business communities to stop buying coal from Meghalaya until the mine owners stop using child labor.