Emergency primarily concerning river: one in Oxford? (6)
I believe the answer is:
crisis
'emergency' is the definition.
(a crisis is an emergency)
'primarily concerning river one in oxford?' is the wordplay.
'primarily' suggests taking the first letters.
'one in oxford?' becomes 'isis' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
The first letters of 'concerning river' is 'cr'.
'cr'+'isis'='CRISIS'
Can you help me to learn more?
(Other definitions for crisis that I've seen before include "Climax point in, say, a fever" , "Crucial stage or turning point" , "Serious or crucial situation" , "Dilemma" , "Time of severe difficulty" .)