Employers, families, the government all have their own reasons for promoting it or turning a blind eye to the fact that it exists. Poor families look upon a child as one more pair of hands to add to the family kitty. Often parents take loans or advance payments from the contractors or employers themselves. Their inability to pay the loans results in the children being unable to leave their jobs. Eventually the child becomes a bonded labourer.
Employers justify child labour by citing various reasons.
Other reasons that are just as important, but not expressed as openly, are that children are paid less than adults for the same kind of work. Often, children work for long hours and in hazardous conditions and are not even paid the minimum wage. The employer manages to exploit them, as they do not have a powerful lobby backing them and there is no one to demand justice for them. Children are not paid while they are on training. The government too prefers to ignore the health and moral implications of the issue.