According to the 2001 census, there are 12.6 million children under the age of 14 engaged in child labour. This is surely a conservative estimate. The government estimates also do not acknowledge the millions of children working in agriculture. Civil society places the number of child labour at a more realistic 40 million or so.
Approximately 70 per cent of children in child labour are in agriculture. Owing to the labour intensive nature of cotton production, the use of child labour in cotton fields, especially for cross-pollination, has increased over the years. Children working in cotton fields are continuously exposed to poisonous pesticides. Apart from the health effects such as headaches, nausea and respiratory ailments borne out by various studies, children working in cotton fields are deprived of schooling. Working long hours in the field means that children cannot attend school regularly or even if they are enrolled, invariably drop out at some point.
Source: No More Excuses To Eliminating Child Labour