According to the U.S. State Department:
Saudi Arabia is a destination for men and women from South and East Asia and East Africa trafficked for the purpose of labor exploitation, and for children from Yemen, Afghanistan, and Africa trafficking for forced begging. Hundreds of thousands of low-skilled workers from India, Indonesia, the Philippines, Sri Lanka, Bangladesh, Ethiopia, Eritrea, Somalia, and Kenya migrate voluntarily to Saudi Arabia; some fall into conditions of involuntary servitude, suffering from physical and sexual abuse, non-payment or delayed payment of wages, the withholding of travel documents, restrictions on their freedom of movement and non-consensual contract alterations. The Government of Saudi Arabia does not comply with the minimum standards for the elimination of trafficking and is not making significant efforts to do so.[137]

Cf. Wikipedia

An examination of a subject that needs far more study.