Over the last decade China developed the longest railway in the world running more than 8,000 miles from the east coast of China to Spain.

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The line crosses China, Russia, Belarus and Poland before splitting up into various European connections.
Over the last year the railway has carried goods between China and Europe at a value of about $25 billion.
The line is now blocked:
Poland’s decision to close its border with Belarus in response to thequadrennial Zapad-2025 military exercises and Russian drone incursion on September 10 has abruptly severed one of the fastest-growing trade arteries between China and the EU.
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The impact of the closure of the Belarusian border is significant. The land corridor already represents 3.7% of all EU–China trade, up from 2.1% a year earlier. While that share remains small compared to seaborne shipments, its importance lies in speed and reliability.
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Poland’s government underlined that the decision was driven by security imperatives rather than economics. Warsaw stated that “the logic of trade” was being replaced by “the logic of security,” underscoring the geopolitical risks attached to the Belt and Road corridors.
The Zapad-2025 military exercises is long over but Poland continues to block the railroad.
Its government is taking Europe's trade with China as hostage to press China to change its policy towards Russia:
Polish Foreign Minister Radosław Sikorski has said that during his meeting with his Chinese counterpart Wang Yi in a suburb of Warsaw on Monday 15 September, he will insist that China put pressure on Russia to stop "a hybrid operation" on Poland’s eastern border, which has led to the closure of Beijing’s key trade route to Europe.
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Tensions escalated in May last year, when a Polish border guard was attacked and killed by a migrant.Polish Prime Minister Donald Tusk accused Belarus and Russia of weaponising migration.
Last year, Warsaw threatened to block the export route to the European Union to secure China’s help. Polish then-president Andrzej Duda raised the border tensions issue during his visit to Beijing, which "helped for a few months", Sikorski said.
"But unfortunately, this hybrid operation has intensified again. So, we need to talk again," he added.
Interestingly the Chinese reporting on the meeting between Wang Ye and Sikorski did not mention the blocking:
At the 4th meeting of Poland-China Intergovernmental Committee on Monday, the two parties exchanged views on the importance of developing effective and economically competitive Eurasian transport corridors and the pivotal role of Poland in this process. The two sides recognized the benefits of providing mutually beneficial services for volumes of goods transported by railway, maritime and air means and of consolidating the existing and potential routes and logistical chains. Both sides expressed their willingness to ensure the safety and accessibility of the China-Europe Railway Express.
I suspect that, behind the scene, less polite words were used by Wang Yi to express the Chinese view on Poland's attempt the hinder the freedom of global trade.
The migrants do not ride on Chinese freight trains. Blocking the railroad connection between China and Europe to prevent migrants from coming through Belarus is a very crude form of blackmail that will hit back.
Should the blockade continue Poland will have to bury all hope of any future investment from China.
Western European companies who depend on the railroad connection for their trade will also become more hostile to Poland.
The coming defeat of NATO in Ukraine will contribute to the end of the military alliance.
Poland's outrageous behavior makes it more likely that the defeat in Ukraine will also help to break up the European Union.
Poland is currently the recipient of the largest EU's agricultural subsidies. Why should Germany and others continue to pay for those when Poland is impeding their trade?