More than 40 million people trapped in slavery globally

Zakir Chowdhury | Barcroft Media | Getty Images

A child working in an aluminium pot-making factory on May 23, 2017 in Dhaka, Bangladesh.

About 40 million people were trapped as slaves last year in forced labor and forced marriages, according to the first joint effort by key anti-slavery groups to estimate the number of global victims of the escalating crime.

The International Labour Organization (ILO), human rights group Walk Free Foundation, and International Organization for Migration said about 40.3 million people were victims of modern slavery in 2016 — but added this was a conservative estimate.

They estimated 24.9 million people were trapped working in the sex trade, in factories, on construction sites, farms and fishing boats, and as domestic workers, while 15.4 million people were in marriages to which they had not consented.

Almost three out of every four slaves were women and girls and one in four was a child with modern slavery most prevalent in Africa followed by Asia and Pacific, the report said.