Over 16 million, or half the world's population of modern-day slaves live in India and Pakistan, according to the inaugural Global Slavery Index published Thursday.
An estimated 30 million people worldwide are living in modern-day slavery, of which 2.1 million are in Pakistan and a staggering 14 million are based in India.
The report by the Walk Free Foundation ranks 162 countries on "modern slavery" by using reports from governments and non-profit organisations as well as statistical estimates.
The Walk Free Foundation's definition of modern slavery includes slavery itself, as well as human trafficking and forced labour, and slavery-like practices such as debt bondage, forced marriage, and sale or exploitation of children.
According to the index, India has the highest total number of enslaved people in the world, between 13.2 million to 14.6 million, followed by China with 2.9 million enslaved people, and Pakistan with 2.1 million enslaved people.
According to estimates by the WFF report, over 1.2 per cent of the Pakistani population is enforced into some form of slavery.
In India, this percentage rests somewhere around 1.13 per cent, while in China it is about 0.22 per cent.
Combined, both India and Pakistan house 54 per cent of the world's population of enslaved people.
The index also ranks countries on a slavery prevalence rating based on factors including ratio to country population.
Mauritania and Haiti rank among the countries with the highest prevalence of modern slavery. An estimated 4 per cent of West African nation Mauritania's population is living in some form of slavery.
Pakistan and India follow the list, ranked third and fourth respectively on prevalence of slavery.
Taken together, countries with the highest numbers of enslaved people - India, China, Pakistan, Nigeria, Ethiopia, Russia, Thailand, Democratic Republic of Congo, Myanmar and Bangladesh - account for 76 per cent of the total estimate of 30 million in modern slavery today.
The Walk Free Foundation is a Perth-based anti-slavery charity founded by Australian tycoon Andrew Forrest. The index has been endorsed by popular leaders including US Secretary Hillary Clinton, former British Prime Minister Tony Blair, current Australian Prime Minister Tony Abbott, and philanthropists Richard Branson and Bill Gates.
The charity hopes the annual index will help governments monitor and tackle what it calls a "hidden crime".