The Green Gang was a criminal organization operating in Shanghai in the early 20th century. It managed, under its leader Du Yuesheng , to control the criminal activities in the entire city of Shanghai. The primary activity of the Green Gang was the trade in opium, which was supported by local warlords. The Green Gang was also involved in the Chinese Civil War, responsible for the White Terror massacre of approximately 5,000 pro-Communist strikers in the City of Shanghai on February 2, 1928, which was quietly approved by Nationalist leader General Chiang Kai-Shek who granted Du Yuesheng the rank of General in the Nationalist army as a result of the massacre.