What is promaja?

In Balkanian promaja is the condition when wind goes through room (e.g. Open two windows on the opposite sides of a room that).

There's a very strong belief that condition can cause you to catch a cold, have headache or pain in the bones.

This belief is so strong that even doctors in Serbia and Macedonia (maybe other countries) suggest that you avoid 'promaja' that is: never keep two windows open!