Dear student, Battle of Plassey happened because of the following reasons - 1) In 1651, the First English factory was set up on the banks of river Hugli. 2) The factory has warehouse alongwith offices. When trade started growing company asked merchants and traders to settle near the factory. 3) After sometime company bribed mughals so that they can get zamindari rights over 3 villages. 4) Company asked Aurangzeb to grant them right to trade duty free and due to Company pressure Aurangzeb granted the right. 5) But, private traders need to pay duty, which company opposed and denied because of which there was loss of revenue for Bengal. 6) And all this led to Battle of Plassey, and company won for the first time in India. Regards