No. 4: India
India has between 13 and 15 million slaves working in numerous industries, and the commercial sexual exploitation of Indian women, men, and transgender people is widespread. Child sex tourism is particularly rampant in religious pilgrimage centers and cities popular for domestic tourism. The 2013 U.S. Trafficking in Persons Report further estimated that 20 to 65 million Indian citizens are enslaved as a result of debt bondage.
In this photo, a male transsexual prostitute sells sex inside a brothel in Mumbai's infamous red light district Kamathipura on Feb. 3, 2011.
Jonas Gratzer/LightRocket via Getty Images