Answer:
The opium war
Step-by-step explanation:
The Opium Wars started between Britain and China related to the opium trade. The political damage between Great Britain and China in the mid 19th century began when the Qing Dynasty decides to put a restriction on the selling of the illegal trafficking of opium. Opium uses cause economic and social problems in China. British defeated China in the Opium wars that helped Europeans nation and the United States establishing treaties for opening ports for trade.