One of the things that Spanish cities do well is clean their streets. Every night whole brigades of men and women dressed in neat green uniforms comb the streets with brooms and hoses. There are also these little washing mobiles that spray water out the sides as they inch down the street. It's quite effective, as one would hope in a country where littering (to say nothing of spitting, dropping burning cigarettes, or sitting on the street drinking) carries no negative value whatsoever.
When I lived in Cordoba many years ago I used to joke that they hosed the streets down with olive oil. No one but me found it funny, admittedly, but I thought it was a fine explanation for why the whole city reeks--in the best possible way--of extra virgin cold pressed. Which is why I found myself chuckling on Monday when I got off the train in Cordoba and was immediately hit with the same green scent.