MANY of India’s “modern slaves” labour in appalling conditions in brick kilns or breaking stones in quarries. Typically they are recruited by agents offering real jobs and then trapped by accepting an advance on earnings, which turns out to be a loan at exorbitant interest that no worker can ever hope to repay. The boss then suggests that the worker bring in his wife and children, and soon the entire family is enslaved. Unpaid debts can be bequeathed from one generation to the next.

Despite having been illegal in India for several decades, such practices continue. Corrupt politicians and police, the caste system and an illiterate workforce with few alternative ways to make a living combine to keep millions in bonded labour. Yet there are examples of activists successfully intervening to free such slaves and, crucially, to keep them free. Some are now being studied to find out what works and could be replicated elsewhere.

One notable example is the Society for Human Development and Women’s Empowerment, an NGO that organises rescues from brick kilns near Varanasi, a city in the northern state of Uttar Pradesh. It seeks out victims, teaches them their rights, organises them into support groups and works with government officials both to free bonded labourers and to make sure they get benefits they are entitled to and school places for their children. It also provides training, especially to women, so that they can earn money in other ways. Some freed workers have even been helped to set up their own brick kilns.

The Freedom Fund is now piloting a “hotspot” strategy that seeks to show how bonded labour can be eradicated from entire districts by helping the most effective NGOs to work together. Grants of up to $200,000 have been given to 17 NGOs in 27 districts in Bihar and Uttar Pradesh, where bonded labour is most prevalent. In the first year, which has just ended, grants of $1.1m freed 2,193 people, of whom 610 can now support themselves without further help. Nearly 6,000 families were helped to enroll in government benefit programmes, and 5,000 officials were trained to enforce the law and give aid to victims.

These efforts, although positive, barely scratch the surface of a huge problem. So the Freedom Fund has recruited the Institute for Development Studies at the University of Sussex and Harvard University’s FXB Centre for Health and Human Rights to study the hotspots to discover what is working and whether it can be scaled up fast. This will include controlled trials comparing districts in which the NGOs work with similar ones where nothing is being done, and will look at everything from whether freed workers find the alternative work that they need to stay free to whether they actually feel freer and more in control of their own lives. The first results are due in a few months.