State media said on Tuesday that about 120 million peasants from China's vast rural areas swarm the cities for work and all try to go home for the holiday, filling all standing room on trains and making access to the toilet impossible during trips often lasting 24 hours or more.

"During the peak travel period last year, some passengers even became deranged on their journeys because of the conditions and jumped out of the carriages," the China Daily said.

The Lunar New Year, which this year starts on 29 January, is the biggest holiday in the Chinese-speaking world, and family reunions prompt arguably the biggest movement of humanity on Earth.

Many supermarkets in southern Foshan had reported a 50% increase in sales of adult diapers for the train trips, the China Daily said in what some local commentators called the "shame of the nation". It did not mention other cities.

Domestic media said railways in China had transported 3.8 million people alone on Monday, an all-time high.