China started the Spring Festival peak travel season Sunday, with tens of millions of passengers, mainly migrant workers and college students, on the move in the world's largest seasonal migration.

The Spring Festival, or Chinese Lunar New Year, fall on Jan. 23 this year. It is the most important traditional Chinese festival for family reunions.

A total of 3.16 billion passenger trips are expected during the 40-day peak travel season, or Chunyun (Spring transportation) in Chinese, up 9.1 percent from a year earlier, according to the National Development and Reform Commission.