They are smoky. Pottery kilns and forges for metal (mainly copper and bronze) generate a lot of smoke. As do the ovens for baking, hearths, cooking fires, and so on. Cremation is really smoky. The bigger the city, the smokier. This is the Lowfires in action.
They are smelly. Animals are slaughtered and butchered in the city, and the offal discarded. Animals (and many humans) urinate and defecate in the streets. Tanning is even worse – it smells awful.
They are colorful. Lime is used to plaster over bricks, walls are often painted garishly, and there’s a lot more decoration than you imagine! Get out of the low-budget movie sets – and think garish and bright!
A big exception to this are the cities built by Sartar and Wilms, which were designed to mitigate a lot of this – especially Boldhome, which is arguably the best designed city I know of in Glorantha.
Glamour on the other hand has all of this to the nth degree, but as per her name, it distracts you from the stench and the smoke with plenty of glitz, noise, and show biz theatrics!