The causes of the Opium War, which erupted in 1839 between Britain and China, stemmed from Britain's opium trade in China. British merchants had been selling opium, grown in British-occupied India, to Chinese consumers, leading to widespread addiction and social problems in China. The Qing Dynasty sought to suppress this trade, culminating in the confiscation of opium stocks in Canton. British merchants and the British government viewed this as a violation of trade rights. Tensions escalated, resulting in the First Opium War, which highlighted issues of sovereignty, trade imbalance, and foreign intervention in Chinese affairs.