Disorder left argon in dark areas on Mars (7)
I believe the answer is:
malaria
'disorder' is the definition.
(malaria is a kind of health problem)
'left argon in dark areas on mars' is the wordplay.
I cannot quite see how this works, but
'left' could be 'al' (I've seen this in other clues) and 'al' is located in the answer.
'argon' could be 'ar' (Ar is the chemical symbol for argon) and 'ar' is present in the answer.
The remaining letters 'mia' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for malaria that I've seen before include "Mosquito-transmitted disease" , "Mosquito-borne fever" , "Disease causing fever transmitted by mosquitos" , "Disease carried by mosquitoes" , "Am a liar (anag) - fever" .)