Ehnancing Production

There is the option to use coins to enhance the production of your cities.

When you purchase enhancement, does it apply to all cities, or just the one that you were in when you purchased it?

just the city in which you purchased the enhancement

It does apply to all cities, but just to make sure you know... It also affects the oasis that you have captured from that city

Kind of a pointless post, but some new players don't realize oasis are affected by enhancement