Best friends Arti and Arti, aged 10, worked together as rag pickers – the lowest of the low in Indian society.
They are Dalits, formerly known as Untouchables, whose families migrated to New Delhi from a small village in Uttar Pradesh.
"In the morning we used to go and collect bottles and plastic, then we would go begging. We'd get about 10 to 20 rupees (approximately 30c) a day," the taller girl tells me.
"We would give that money to our mum and she would run the household with it," her friend says, with a shrug of resignation.
We are at the Delhi Child Restoration Project near a sprawling slum which houses hundreds of people.
From the age of four they spend 12 hours a day collecting waste to sell to scrap dealers, who supply a growing number of recycling centres. With a burgeoning middle class in a population of 1.2 billion, India generates 55 million tonnes of solid waste each year.
In this city alone there are an estimated 300,000 rag pickers living on the margins of society.
"When we first came in it was very difficult to digest the lives these children live," says centre manager Raifiel Jos.
"(They) are facing all sorts of abuse: physical, sexual, emotional. They have nothing. Anything you can name that a child should have, they have none of it."