China wants to work with Russia to reform the "gray customs clearance" system and reverse a decline in bilateral trade, state media reported. China is Russia’s second-largest trading partner, but trade plummeted 39% during the first five months of this year from a year earlier. Under the "gray customs" system, Chinese traders have often been expected to pay bribes to officials at the border, despite having their official paperwork in order. On June 29, Russian police raided Cherkizovsky market in Moscow, confiscating Chinese imported goods lacking formal customs clearance valued at US$5 billion from Chinese traders and detaining 150 Chinese citizens for expired visas. Russian authorities subsequently deported 80 Chinese businessmen for protesting the shutdown of the market. While most of the goods have been returned to their Chinese owners, Beijing’s concerns about the "gray customs" system have yet to be resolved. The two countries are also exploring a currency swapping policy to strengthen bilateral trade. China has a US$1.37 billion trade deficit with Russia.