India, Oct. 16 -- The historic Walled City of Old Delhi is barely left with its original stone walls. No worries. The much larger modern-day megapolis of New Delhi has hundreds of thousands of individual brick walls that flank its roads and streets, colonies and slums, bazars and suburbs. These walls are full of idiosyncratic personalities, and tend to be plastered with all sorts of advertising flyers. Some ads are banal, some are funny, some are sad, and some are shockingly crude. Together, the wall flyers show the city's inner life, inadvertently betraying the anxieties and aspirations of its citizens.

One afternoon, a young man is seen stamping a roadside wall with such flyers near the New Delhi railway station-see photo. He is puttin...