India's rapid economic growth — and its long-standing poverty — are also reflected in the census. More than half of all Indian households now have cellphones, but fewer than half have toilets.

The government began releasing the data last month, and it shows a country where the middle-class is expanding rapidly.

 

"Does growth really trickle down? I think this is the start of that," Anand says. "And access to basic products, or access to aspirational products, is usually the first signal of that kind of thing happening."

In a slum in the heart of New Delhi, the Indian capital, there are signs of this improvement in personal wealth, amid the public squalor.