Why was the Battle of Buxar fought ?

The Battle of Buxar (1764) was primarily caused by the conflict between Mir Qasim, the Nawab of Bengal, and the British East India Company over trade privileges and administrative interference [t1][t7]. After being defeated in several skirmishes in 1763, Mir Qasim fled to Awadh (Oudh) [c2][t6]. There, he formed a formidable anti-British alliance with Shuja-ud-daulah, the Nawab of Oudh, and the fugitive Mughal Emperor Shah Alam II [c1][c3]. These three allies joined forces with the shared objective of expelling the English from Bengal and restoring their respective sovereign authorities [t2][t7]. On October 22, 1764, this confederacy clashed with the British forces led by Major Hector Munro at Buxar [c3][t5]. The decisive British victory led to the Treaty of Allahabad in 1765, which fundamentally altered the political landscape of India by granting the Company Diwani rights [c5][t2].

Sources

1. [1] History , class XI (Tamilnadu state board 2024 ed.) > Chapter 16: The Coming of the Europeans > Battle of Buxar (1764) > p. 258
2. [2] Modern India ,Bipin Chandra, History class XII (NCERT 1982 ed.)[Old NCERT] > Chapter 4: The British Conquest of India > Courtesy; National Archives of India, New Delhi > p. 70
3. [3] Rajiv Ahir. A Brief History of Modern India (2019 ed.). SPECTRUM. > Chapter 5: Expansion and Consolidation of British Power in India > The Battle > p. 91
4. [4] Rajiv Ahir. A Brief History of Modern India (2019 ed.). SPECTRUM. > Chapter 4: India on the Eve of British Conquest > Weak Rulers after Aurangzeb—An Internal Challenge > p. 63