According to report of Walk Free Foundation, the Global Slavery Index estimates that 40.3 million people worldwide were subjected to modern slavery in 2016.
It has been published by the International Labour Organization and The Walk Free Foundation, in partnership with the International Organization for Migration.
Modern slavery - involving the use of violence, deception and threats to trap people in forced labour, sexual exploitation and domestic servitude.
India was home to the largest total number with an estimated 8 million slaves among its 1.3 billion population.
North Koreahas the highest concentration of modern slavery where one in 10 people are in this condition.
The index lists Eritrea, Burundi, the Central African Republic, Afghanistan, Mauritania, South Sudan, Pakistan, Cambodia and Iran as the worst offenders after North Korea.
The reason for such slavery is import of USD 354 billion worth of goods by G20 countries.
The report cites coal, cocoa, cotton, timber and fish as among the products.