Allocated (8)
'allocated' is the definition.
(rationing is a kind of allocating)
This is all the clue.
(Other definitions for rationed that I've seen before include "Limited (a supply)" , "Apportioned out" , "issued shares" , "Doled out in Rodentia" , "Allowed fixed quantity only as in times of scarcity" .)
(Other definitions for allotted that I've seen before include "Portioned out" , "Distributed in shares" , "Earmarked" , "Parcelled out" , "'Assigned, distributed (8)'" .)