As a child growing up in one of Brazil’s poorest regions, I was used to seeing well-off families take in girls from poorer ones to come live in their homes and be brought up as one of their own. This was seen as an act of kindness. It was only much later that I came to see it for what it really was: these young girls, who would do all the domestic chores all day long in return only for food and a roof over their heads, were in fact modern slaves.

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There are 21 million modern slaves in the world today, most of them women and girls hiding in plain sight in poor and rich countries alike – 7% of today’s slaves live in North America or the European Union. From trafficking and sexual exploitation to work in private homes, agriculture, fishing, construction and manufacturing, modern slavery is not only a crime, it is big business. It generates some $150bn in illegal profits every year, according to an estimate by the International Labour Organization (ILO).

Poverty is at the root of it, as is lack of awareness by both victims and the general public. Forced labor affects the most vulnerable and least protected people, perpetuating a vicious cycle of poverty and dependency. Women, low-skilled migrant workers, children, indigenous peoples and other groups suffering discrimination on different grounds are disproportionately affected. And many victims don’t even consider themselves to be slaves – working to pay off a debt passed down through generations, or being a servant in a private home from dusk to dawn is the only life some have ever known. At the same time, you may be eating food picked by modern slaves, or wearing clothes made with slave labor without realizing it.

To fight slavery, then, we must first and foremost fight poverty and advance social justice so that everyone will have the same opportunities. We also need robust laws that are enforced, inspections, social responsibility on the part of employers, awareness on the part of consumers, rehabilitation of victims and harsh penalties for those found guilty of enslaving people. Brazil is a case in point. In the last two decades the country has made remarkable progress in tackling slavery with a mix of strong policies and concerted action, an example to admire.

One of the most effective tools in Brazil’s efforts to eradicate slavery is a register compiled by the government that lists individuals and businesses found using slave labor. Those on the “dirty list”, as the register is known, are fined and remain on it for a minimum of two years during which they cannot access public funds. Before they can be removed from the register they need to show proof that they no longer use slave labor.

The “dirty list” has been temporarily suspended by Brazil’s supreme court following a request by a business interest group. Anti-slavery groups are mounting a spirited effort to have the register reinstated, as its demise would be a major setback in the fight against slavery. The whole thing shows both that with the right instruments and policies countries can combat modern slavery, and that there is no room for complacency; on the contrary, we must step up the fight or risk setbacks.

The ILO has a new protocol on forced labor that gives countries a powerful tool to tackle slavery. The first international treaty on slavery in more than 80 years, it was adopted by ILO members in 2014 and takes into account new forms of slavery, including trafficking for sexual or labor exploitation and debt bondage. It also requires countries not only to criminalize slavery and punish perpetrators but to prevent it, and to offer protection and remedy to victims.

The protocol requires two national ratifications before it enters into force. The ILO is launching a campaign to persuade at least 50 countries to ratify it by 2018. Because to live in a world with millions of slaves demeans us all.