Clinically defined as urine output of less than 100 ml in 24 hours, anuria indicates either urinary tract obstruction or acute renal failure due to various mechanisms.[…]Anuria is rare; even with renal failure, the kidneys usually produce at least 75 ml of urine daily.
Source: wiktionary
Changes in urinary pattern such as polyuria, oliguria, anuria, enuresis, and excessive thirst can be associated with tubular dysfunction.
Source: wiktionary
It goes without saying, therefore, that obstructive anuria can occur only if the outflow from both kidneys or from the only functioning kidney is obstructed.
Source: wiktionary