Why did the Taliban regime collapse in 2001?

The collapse of the Taliban regime in 2001 was primarily triggered by the September 11 attacks on the United States, which were orchestrated by al-Qaeda while operating from within Afghanistan.12

Following the attacks, the administration of U.S. President George W. Bush demanded that Taliban leader Mullah Mohammed Omar extradite al-Qaeda leaders and dismantle the terrorist network. When the Taliban refused to comply, the United States and its allies initiated Operation Enduring Freedom on October 7, 2001.12

The regime’s fall was achieved through a combination of:
* Air Campaigns: U.S. and British forces conducted intensive bombing of Taliban targets.12
* Military Partnerships: The United States provided significant logistical support, arms, and coordination to the Northern Alliance, a coalition of anti-Taliban factions that had been resisting the regime since the mid-1990s.123
* Ground Offensives: Supported by U.S. special forces and air power, Northern Alliance and other anti-Taliban forces captured key cities, including Kabul in mid-November and the Taliban’s spiritual stronghold of Kandahar on December 6, 2001, effectively ending the regime's power.12