According to the Wall Street Journal, in 2016 there were 18 million slaves in India.
https://blogs.wsj.com/indiarealtime/2016/06/02/india-has-the-most-people-living-in-modern-slavery/
From the WSJ article you referenced:
“from domestic to sexual to bonded and child labor. The term refers to a situation in which a person has taken away another’s freedom so they can be exploited.”
A part of the above definition does not look like the classic understanding of slavery that we have been used to.
Let’s talk about child labor... here are some questions:
1) If the child does not want to work in the place, is he still FORCED to work there against his will?
2) Can the child be “sold” to another owner?
If the answer is “No”, then this is a modern redefinition of slavery as we understand it.