Indian activists have dared the head of the country's planning body to live on half a dollar a day to test his claim that it is an adequate sum to survive.

Last week the Planning Commission said the amount is "adequate" for a villager to spend on food, education and health.

But prominent campaigners Aruna Roy and Harsh Mander asked the panel chief, Montek Singh Ahluwalia, and members to either withdraw the figure or resign.