India's government launched an online portal on Tuesday to register, rescue and rehabilitate child workers, as part of a drive to curb the exploitation of millions of minors. India's 2011 census found over 4 million labourers aged between five and 14, out of 168 million globally, but campaigners say millions more are at risk due to poverty. The portal - Platform for Effective Enforcement for No Child Labour, or Pencil - aims to bring together officials, charities and police at federal, state and district level to share information and coordinate on child labour cases.