On the eve of the Lunar New Year, train stations and airports across China have experienced their highest passenger traffic, with millions of people returning home to celebrate the holiday with their families. Annual population mobility is expected to hit a record high.

Chinese New Year (Year of the Snake) begins on Wednesday.

According to official news agency Xinhua, during the traditional 40 days before, during and after the holiday, inter-provincial passenger traffic across all modes of transportation is expected to reach about 9 billion.

Train and air travel are expected to hit “record highs” during this year’s immigration period, Xinhua said.

The Ministry of Transport said it expects the number of train passengers to reach 510 million and the number of air passengers to reach 90 million during this period.

According to China Railway Corporation, Saturday is the “main peak” at the station before the holiday. The company has added thousands of trains to meet demand.

The company said it uses data on ticket sales and waitlists to predict and regulate supply.

Large-scale population migration occurs around the Spring Festival as many people move to other provinces to work and study for better opportunities.

Many factories are already closed for the holidays, and these workers traditionally go home earlier than others.