There are 30 million people enslaved across the globe and nearly half of them are in India, according to the Global Slavery Index 2013.
These slaves are trafficked into sexual servitude, forced manual labor, debt bondage and even some born into slavery.
The report was issued by Australian-based human rights group Walk Free, which surveyed 162 countries and discovered slavery in all of them.
The index defined slavery as the “possession or control of people to deny freedom and exploit them for profit or sex, usually through violence, coercion or deception.” This includes forced marriage, children abducted to serve in wars, and indentured servitude.
"Today some people are still being born into hereditary slavery, a staggering but harsh reality, particularly in parts of West Africa and South Asia," the report said. "Other victims are captured or kidnapped before being sold or kept for exploitation, whether through 'marriage', unpaid labor on fishing boats, or as domestic workers. Others are tricked and lured into situations they cannot escape, with false promises of a good job or an education."
There were 10 countries that accounted for three quarters of slavery in the world: India; China (2.9 million); Pakistan (2.1 million); Nigeria (701,000); Ethiopia (651,000); Russia (516,000); Thailand (473,000); Democratic Republic of Congo (462,000); Myanmar (384,000); and Bangladesh (343,000).
Countries like Great Britain and Finalnd have much lower rates, but researchers say they discovered those countries still grossly underestimate the problem of slavery there.
"They've been allocating resources against this crime according to the tiny handful of cases that they've been aware of," said Kevin Bales, lead researcher and professor at the Wilberforce Institute for the Study of Slavery and Emancipation at Hull University. "Our estimates are telling them that the numbers of people in slavery - whether it's in Great Britain or Finland or wherever - in these richer countries actually tends to be about six to 10 times higher than they think it is."
Walk Free CEO Nick Grono said the annual index is meant to provide governments and activists with a baseline for the fight against slavery.
"This kind of data hasn't been out there before," Grono told Reuters. "It's a multi-year effort, and next year we'll have a much better picture of where slavery is and what changes there are. If you can't measure it, you can't devise policy to address it."