New Delhi, April 30 -- It is hard to put into words why a photographer walks a city collecting images like beads. Perhaps it is all but a rehearsal to remember in the present that a place is always in flux, always being altered by time before one fully knows it. When this feeling thickens, you return to these fragments-your archive-and see again that even in silence, something at the edge of the frame that you didn't notice has lingered a little longer than it could in the world. The walk is not about destination but accumulation, a slow indexing of the world. In this sense, every photographer is also a note maker, part of a lineage that runs from Eugene Atget wandering Paris with his camera, to those who came after, carrying cities not a...