מלכים ב, פרק כ״ה, פסוק ב׳

The siege of Jerusalem was a continuous, exhausting event that slowly ground down the strength of its residents until they reached a breaking point. The city was completely sealed off, trapped as enemy forces surrounded it from every possible direction [מצודת דוד]. This tight blockade lasted for two full years, continuing right up to the eleventh year [ביאור שטיינזלץ] of King Zedekiah's rule [אברבנאל].

As time passed, the prolonged isolation caused a severe famine within the city walls. The hunger weakened the defenders so much that by the time the Chaldean forces finally broke through the defenses, the residents were entirely unable to resist or fight back. The standoff took so long that King Nebuchadnezzar of Babylon likely decided not to stay at the front lines. Instead, he relocated to the city of Riblah, leaving his army under the command of Nebuzaradan to maintain the siege until the city was finally breached [אברבנאל].