Chunyun,  also referred to as Spring Festival travel season, or Chunyun period, is a period of travel in China with extremely high traffic load [l?ud](the largest amount of something that a vehicle can carry)around the time of the Chinese New Year. The period usually begins 15 days before the Lunar New Year's Day and lasts for around 40 days. The number of passenger journeys during the Chunyun period has exceeded the population of China, hitting(達到某一數量） 2.26 billion in 2008. For comparison, this equals the number of rail journeys undertaken（承擔） in the UK during the entire 2005-2006 year.It has been called the largest annual human migration（移動，遷移） in the world. Rail transport experiences the biggest challenge during the period, and a myriad （極大數量的）of social problems have emerged（出現）.

       Three main factors are responsible for the heightened（加深的，加劇的） traffic load during the Chunyun period.

       First, it is a long-held （根深蒂固的）tradition for most Chinese people to reunite with their families during Chinese New Year. People return home from work or study to have Reunion dinner with their families on New Year's Eve（除夕）. Since the Chinese economic reforms of the late 1970s, new economic opportunities have emerged, often at a considerable distance from people's hometowns. Places such as the Special Economic Zones and the wealthy coastal regions offer employment and often, a more sought-after（被追捧的） lifestyle. Consequently, there has been a massive（大量的） migration from rural to urban areas over the course of the last few decades, reminiscent（使人想起某事的） of other industrial revolutions around the world. The number of these migrant workers was estimated at 50 million at 1990 and unofficially estimated at 150 million to 200 million in 2000 . During the Chunyun period, many of these laborers return to their home towns.

       Second, Chinese education reforms have increased the number of university students, who

often study outside of their hometown. The Spring Festival holiday period falls around the same time frame as their winter break. Among the 194 million railway passengers of the 2006 Chunyun period were 6.95 million university students.

       Finally, because the Spring Festival Period is among the two week-long holiday periods in

the People's Republic of China (the other being National Day, Oct 1), many people choose to travel for pleasure around this time. Tourism in mainland China is reaching record levels, further adding to the pressure on the transportation system.

       These factors exacerbate（加劇，使...更嚴重） current problems with China's current inter-city transportation systems. The railway network is insufficient to handle the number of passengers, and does not reach enough places. The locations not serviced by rail must rely on bus transport, which faces problems such as inadequate（不足的） equipment and road network.