This post by Dan Zambonini offers an explanation for why the east of cities are usually poorer than the west:
The reason for this is that in much of the northern hemisphere, the prevailing winds are westerlies – blowing from west to east. The massive, unchecked pollution from these early industries would therefore drift eastward, making the air quality much lower in the east end of cities, lowering the desirability (and price) of the housing. Middle classes preferred the cleaner west ends.
This is certainly one possible factor for why rents in the Western suburbs of Bombay are so much higher than those in the East. (Compare Andheri West and Andheri East, or Bandra West and Bandra East.) But I’m sure there are other, specific local factors as well. What do you think those are?
(Link via Marginal Revolution.)