As David has mentioned, it could be hot in Southern Africa and wearing shorts was perfectly acceptable in many environments along with an open shirt neck (no tie). At one point in the 70s/80s there was an attempt to formalize the dress in what was called a "safari suit". The link doesn't really capture the african version I am talking about and I can't seem to find any other suitable pictures.
There was no belt (which the link sometimes hints to) and the shorts were about mid-thigh length. Also you wore long socks (to about 3/4 calf) and (often mocked by comedians) a comb tucked into the top of one of the socks.
Those aspiring to elegance (or trying to hide a trachiotomy) would wear a cravat.
People welcomed the rain because it cleared out the pollution.
One of the things I remember most about Taiwan was that on the hills alongside the motorway there were these huge water channels made of concrete up and down the mountains. They were everywhere. When it rains in Taiwan it must really RAIN, or am I misinterpreting the structures.
The pollution is, I am sure, much better now in Taipei/Taiwan. I lived in Beijing in 1996/97, which was pretty bad. I lived in Los Angeles, well I was four or five at the time, during the mid-1970s; that was not a particularly good time for pollution there.
Notes: I assume they are working women (not students or shop-a-holics) because they have badges. I also assume that the photographer selected them for their style, age etc, and they may not be typical. And I know what my wife would say: "I'm too old to dress like that (at least if you're around)"
Finally, since this is a serious research project, note that none of them appear to be wearing any wearable electronics such as Pebble smart watches....