Mostly light brown dust in the air? (4)
I believe the answer is:
haze
This could be a double definition.
'mostly light brown dust' is the first definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
'air?' is the second definition.
The definition and answer can be both types of natural phenomena as well as being singular nouns.
Maybe there's a link between them I don't understand?
'in the' is the link.
Can you help me to learn more?
(Other definitions for haze that I've seen before include "Mistiness" , "Vapour" , "Slight atmospheric mist" , "A thin mist, perhaps from heat" , "Daze, fog" .)