Eight suspects have been detained for illegally selling tobacco for e-cigarettes.
The suspects are reported to have purchased over 12 million yuan ( million) worth of tobacco from Japan and sold to buyers in Shanghai, Guangzhou, Nanjing and Wuxi.
The suspects did not have the required license to sell tobacco in China, police said.
Two of the suspects traveled to Japan at the beginning of last year and purchased cartons containing 10 packs, or 200 "cartridges" of tobacco, for prices ranging between 270 to 340 yuan each.
They would bring the tobacco with them or ship it via international courier companies. The rest of the suspects were involved in warehousing the goods and selling them to domestic buyers.
During a raid on January 18, police discovered over 6,700 cartons of illegal tobacco.