Most of them are children of migrants who have come to Delhi in search of work on construction sites or as casual labour. They live on the margins, in shanties hidden from the view of those who drive by on the vista-wide roads of the city, shanties at the end of beaten paths leading off through grass and scrub. And they do go to school, which for them is conducted under the pre-fab concrete structures used to build flyovers and elevated metro tracks. In small groups they make their way to an informal school on the yamuna riverbed. There’s only one teacher and he works for free. but he’s making a big difference.