I bet that this isn't the only case where something like this is going on...
Back in '97, for quite a few months, twice per day, I had to deal with
this . (Scroll down to the "Barnyard odor" article.)
Turns out that a nearby building had an illegal sewer hookup, with raw sewage flowing into the storm drainage system of the underground trains. The authorities finally figured out the source when toilet tissue started washing up out of the drains after a heavy rain.
YUCK!!!!
