British acquired political control in India after which battle?

Battle of Plassey

From the mid-eighteenth century, there was a new phase of change. Commercial centres such as Surat, Masulipatnam and Dhaka, which had grown in the seventeenth century, declined when trade shifted to other places. As the British gradually acquired political control after the battle of Plassey in 1757, the trade of the English East India Company expanded, and colonial port cities such as Madras, Calcutta and Bombay rapidly emerged as the new economic capitals.