Final answer:
In December 2001, Kandahar was abandoned as the last major town under Taliban control.
Step-by-step explanation:
In December 2001, Kandahar was abandoned; it was the last major town under Taliban control. After facing the United States-led military intervention in response to the September 11 attacks due to their refusal to hand over Al Qaeda leader Osama bin Laden, the Taliban lost control over major cities in Afghanistan.
The Northern Alliance, along with US and British forces, managed to oust the Taliban from power in the capital, Kabul, in November 2001, but the Taliban continued to have a stronghold in Kandahar.
Eventually, Kandahar, being the spiritual home of the Taliban and located in a region where support for the Taliban has been historically strong, was also taken over by the anti-Taliban forces, marking a significant moment in the conflict.
Despite the initial successes of the coalition forces, the Taliban sustained its support by retreating into the tribal areas along the Afghan-Pakistan border, leading to an ongoing conflict with NATO and US forces in the region.
Hence, In December 2001, Kandahar witnessed the withdrawal of Taliban forces, marking the relinquishment of the last significant town under their control.