The 2016 Global Slavery Index found there to be many more "modern slaves" than previously recognized, with nearly two-thirds of the global total in Asia. Modern slavery has become a catch-all term to describe human trafficking, forced labor, debt bondage, sex trafficking, forced marriage and other such exploitation, DW wrote.
India has the highest number of people trapped in slavery at 18.35 million, followed by China (3.39 million), Pakistan (2.13 million), Bangladesh (1.53 million) and Uzbekistan (1.23 million), the report said.
In terms of slavery as proportion of the population, North Korea led with 4.37% of the hermit country's 25 million population enslaved. The report noted that North Korea also has done nothing to combat slavery and the state endorses it.
Uzbekistan followed North Korea in terms of proportion of the population enslaved, with 3.97% of its people in forced labor conditions in the cotton sector.
Modern slavery was found in all 167 countries in the index.
Read alsoReuters Exclusive: ISIS ruling on sex slavesEurope has the lowest prevalence rate, but the Walk Free Foundation said the continent was a source and destination for forced labor and sexual exploitation. It warned that people fleeing conflict and poverty could increase incidences of enslavement in Europe.
The startling figure contrasts with the United Nation's International Labor Organization, which estimates 21 million people are forced into labor. The ILO's number does not take into account the broader definition of modern slavery used by the Walk Free Foundation.
Modern slavery means a person is forced to do work and cannot leave due to threats, violence, coercion, abuse of power or deception.
The Walk Free Foundation called on governments to do more to combat slavery and urged businesses to ensure their supply chains are free of slaves.