Poland has threatened to block a key rail route for exporting Chinese goods to the European Union as part of a diplomatic strategy to address the migration crisis on its eastern border, according to Bloomberg. President Andrzej Duda used his state visit to Beijing in late June to link the issues of migration and freight transit through the Belarusian border, according to sources familiar with the negotiations. Since then, the number of illegal border crossings from Belarus to Poland has significantly decreased. For the past three years, Alexander Lukashenko has been attempting to create a seve…