As a resident of Delft (and originally hailing from Mumbai) I can vouch for the subjective difference in average noise levels one would be exposed to - coming from a bustling city filled with "layers" of various sounds (trains, honks, crowd, etc.) to a town where most of the sound seems to come from people, the difference is considerable.
Naturally, Delft cannot be compared to Mumbai (whose population is more than the entire population of the Netherlands), but having had first-hand experience of spending a considerable amount of time in both places, I simply cannot overstate the peace of mind felt with extremely low noise levels. As far as a good solution to noise levels in cities like Mumbai goes, there's a whole lot to be done - and a Delftian approach certainly wouldn't work.
Naturally, Delft cannot be compared to Mumbai (whose population is more than the entire population of the Netherlands), but having had first-hand experience of spending a considerable amount of time in both places, I simply cannot overstate the peace of mind felt with extremely low noise levels. As far as a good solution to noise levels in cities like Mumbai goes, there's a whole lot to be done - and a Delftian approach certainly wouldn't work.