Walking above the village of Mehrauli on Delhi’s southern perimeter, we pass a woman with a half-empty bottle of water—one of several we have already noticed since daybreak. Dressed immaculately in a brightly-colored sari, she emerges from behind a prickly bush on a tract of waste ground. If she were a man we might not have merited such discretion. India is about the only country in the world where you actually see human adults defecating. When traveling by road or rail you can be struck by the image of men squatting openly, impervious to the public gaze. The UN estimates that 600 million people—or 55 per cent of the Indian population—still defecate out of doors. The practice is clearly born of necessity in a crowded country where the development of public amenities has conspicuously failed to keep pace with economic and demographic growth.