Needs a clean up: Fingermarks can be clearly seen as a member of staff
   wipes the side of the train with his hand
   Getting the dust away: A Chinese worker cleans a high-speed train at a
   maintenance station in Beijing, China
   Getting the dust away: A Chinese worker cleans a high-speed train at a
   maintenance station in Beijing, China

   Getting the dust away: A Chinese worker cleans a high-speed train at a
   maintenance station in Beijing, China

--
   journey went through the current red smog alert zone.

   China's high-speed trains travel at their highest speed at 300km an
   hour. The journey between the two cities takes around five hours on
   average.
--
   This comes just after China released a nationwide red smog pollution
   warning with visibility in some areas down to just 160 feet.
   In the middle: A high-speed bullet train is covered in dirt due to
   heavy smog after travelling through smoggy areas
   In the middle: A high-speed bullet train is covered in dirt due to
   heavy smog after travelling through smoggy areas

   In the middle: A high-speed bullet train is covered in dirt due to
   heavy smog after travelling through smoggy areas
   The images prompted people online to post their own images of filthy
--
   The images prompted people online to post their own images of filthy
   trains travelling through northern China
   Working hard: A Chinese worker cleans a Chinese high-speed train
   covered in dirt due to heavy smog
   Working hard: A Chinese worker cleans a Chinese high-speed train
   covered in dirt due to heavy smog

   Working hard: A Chinese worker cleans a Chinese high-speed train
   covered in dirt due to heavy smog
   Air pollution: The recent smog is both dense and moist meaning that the
--
   And one user said: 'Trains can be washed but not our lungs.'

   Chinese workers clean a China Railway High-Speed train that has been
   coated in thick heavy smog
   Chinese workers clean a China Railway High-Speed train that has been
   coated in thick heavy smog

   Chinese workers clean a China Railway High-Speed train that has been
   coated in thick heavy smog

--
   with visibility in some areas down to just 160 feet
   Need a bigger mop: Chinese workers team up together to clean the top of
   a high-speed rail carriage in Beijing
   Need a bigger mop: Chinese workers team up together to clean the top of
   a high-speed rail carriage in Beijing

   Need a bigger mop: Chinese workers team up together to clean the top of
   a high-speed rail carriage in Beijing
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