wind direction for those living near something unpleasantly odoriferous such as a swamp or an industrial estate
I can testify to the importance of wind direction as I went to school close to a sewage processing plant. Most days everything was fine but occasionally the wind wasin the wrong direction!
Both the sewage works and the school are still there but the problem seems to have gone away. I assume the advances in sewage processing technology have worked their magic and today's pupils don't have the same unpleasant experience as I did many years go.