No. 3: Pakistan
The Asian Development Bank estimates that 1.8 million people in Pakistan are bonded laborers -- people forced to work off debts owed to an employer. These debts are often passed down generationally, and workers can be trapped into labor that yeilds little or no pay at all. The Federal Bureau of Statistics estimates that Pakistan has 3.8 million child laborers between the ages of five and 14. Children and "low-caste" families are particularly vulnerable to becoming bonded laborers in Pakistan's brick-making industry.
Above, a child tries not to spill the water he is carrying at a brick-making area on the outskirts of Lahore on July 8, 2012.
ROBERTO SCHMIDT/AFP/Getty Images