Most polio can unfortunately be found all over the world (12)
I believe the answer is:
cosmopolitan
'found all over the world' is the definition.
I can't tell whether this defines the answer.
'most polio can unfortunately' is the wordplay.
'unfortunately' indicates anagramming the letters (a bad or unfortunate spelling).
'most'+'polio'+'can'='mostpoliocan'
'mostpoliocan' with letters rearranged gives 'COSMOPOLITAN'.
'be' is the link.
Can you help me to learn more?
(Other definitions for cosmopolitan that I've seen before include "Familiar with many cultures" , "In a magazine" , "At ease in many different cultures" , "cocktail for a > man of the world" , "Familiar with many parts of the world" .)