Indian police have rescued more than 180 Nepali men and women in a major operation near the border with Myanmar after activists raised suspicions they were being trafficked into forced labour.
Police in the northeast Indian state of Manipur said they had arrested four Nepalis in the main city of Imphal and charged them with human trafficking. Other arrests had been made elsewhere, they said.
"We got specific inputs from certain NGOs (non-government organisations) who were alerted by relatives that their family members had gone without their knowledge and permission," said Manipur's director general of police L.M. Khaute.
"So there was circumstantial evidence that this could be human trafficking," he told the Thomson Reuters Foundation.
Campaigners say traffickers are using the road between India and Myanmar to transport workers illegally to other Southeast Asian countries or the Middle East without going through Indian airports, where checks have intensified.
Most of the 183 people rescued so far had either flown to India from Nepal or travelled by road. Campaigners suspect others may have already crossed into Myanmar.
"This is an easy road route for labour trafficking," said Hasina Khabhih, founder of Impulse NGO Network, which helps state authorities conduct rescue operations.
Campaigners who spoke to the rescued men and women said they had been promised work permits and new passports and in some cases the agents had kept their original documents.
"There is complete labour exploitation in such cases," said Bishwo Khadka, head of Maiti Nepal, one of the charities that tipped off Indian authorities.
"They are not provided what they have been promised. There are hundreds of cases of girls working in the Middle East who call us for help because they are confined and are not paid what they were promised," Khadka said by phone from Nepal.
Khadka was to fly to India on Tuesday to help repatriate the rescued Nepalis.
South Asia is the fastest-growing and second-largest region for human trafficking in the world after East Asia, according to the United Nations Office for Drugs and Crime (UNODC).
Victims, mostly from poor rural areas, are lured by traffickers with promises of good jobs, only to find themselves forced to work in fields or brick kilns, enslaved in homes as domestic workers, or as prostitutes.
Traditionally, traffickers have used Nepal as a transit point to send women to the Gulf. But trafficking through Myanmar is now on the rise, police say.