thumb|British assault on Canton during the First Opium War, May 1841 Some competition came from the newly independent United States, which began to compete in Guangzhou, selling Turkish opium in the 1820s. Portuguese traders also brought opium from the independent Malwa states of western India, although by 1820, the British were able to restrict this trade by charging "pass duty" on the opium when it was forced to pass through Bombay to reach an entrepot. Despite drastic penalties and continued prohibition of opium until 1860, opium smuggling rose steadily from 200 chests per year under the Yongzheng Emperor to 1,000 under the Qianlong Emperor, 4,000 under the Jiaqing Emperor, and 30,000 under the Daoguang Emperor.Wertz, Richard R. "Qing Era (1644–1912)". iBiblio. 1998. Retrieved on September 21, 2007. This illegal sale of opium, which has been called "the most long continued and systematic international crime of modern times",John K. Fairbanks, "The Creation of the Treaty System' in John K. Fairbanks, ed. The Cambridge History of China, vol. 10 Part 1 (Cambridge University Press, 1992) p. 213. cited in became one of the world's most valuable single commodity trades, and between 1814 and 1850, sucked out 11 percent of China's money supply.
thumb|British assault on Canton during the First Opium War, May 1841 Some competition came from the newly independent United States, which began to compete in Guangzhou, selling Turkish opium in the 1820s. Portuguese traders also brought opium from the independent Malwa states of western India, although by 1820, the British were able to restrict this trade by charging "pass duty" on the opium when it was forced to pass through Bombay to reach an entrepot. Despite drastic penalti,es and continued prohibition of opium until 1860, opium smuggling rose steadily from 200 chests per year under the Yongzheng Emperor to 1,000 under the Qianlong Emperor, 4,000 under the Jiaqing Emperor, and 30,000 under the Daoguang Emperor.Wertz, Richard R. "Qing Era (1644–1912)". iBiblio. 1998. Retrieved on September 21, 2007. This illegal sale of opium, which has been called "the most long continued and systematic international crime of modern times",John K. Fairbanks "The Creation of the Treaty System' in John K. Fairbanks, ed. The Cambridge History of China, vol. 10 Part 1 (Cambridge University Press, 1992) p. 213. cited in became one of the world's most valuable single commodity trades, and between 1814 and 1850, sucked out 11 percent of China's money supply.