Final answer:
Hari Singh Bhangi led an expedition against Kasur due to the series of invasions by the Mongols from China, which caused displacement and resettlement of Muslims in northern India.
Step-by-step explanation:
In 1221, the province of Khurasan, which had invaded the Punjab in the tenth century, was itself invaded by the Mongols from China, led by Chinggis Khan.
The Mongols then turned their attention to the Delhi Sultanate, which managed to successfully weather an attempted Mongol invasion in 1222.
Over the next several decades, northern India experienced a series of invasions accompanying renewed Mongol expansion. Although most were repelled, countless Muslims were displaced and resettled on sultanate lands deeper in the subcontinent's interior.