Originally Posted by Sarn

In the 17th and 18th centuries demand for Chinese goods (particularly silk, porcelain, and tea) in Europe created a trade imbalance between Qing Imperial China and Great Britain. European silver flowed into China through the Canton System, which confined incoming foreign trade to Canton and the Chinese merchants of the Thirteen Factories. To counter this imbalance, the British East India Company began to auction opium grown in India to independent foreign traders in exchange for silver, and in doing so strengthened its trading influence in Asia. The opium was transported to the Chinese coast where local middlemen made massive profits selling the drug inside China. The influx of narcotics reversed the Chinese trade surplus, drained the economy of silver, and increased the numbers of opium addicts inside the country, outcomes that worried Chinese officials.
https://en.wikipedia.org/wiki/First_Opium_War

Interesting how it will be solved now)