Shanghai, China – Hundreds of millions of people, including migrant workers and students, will crisscross the country to reunite with their families during the Chinese Lunar New Year Festival.

For most of them, it’s the only time of the year when they can see their loved ones. Some 3.5 billion journeys will be made in just over a month, exacerbating existing problems with inter-city transport in China.

Travel infrastructure here has been rapidly developing in recent years. The online ticket sale system has been improved, which has eased the queues at stations, but capacity still can’t satisfy needs at peak times – often leaving people with only “standing tickets”.

In many cases, those who do manage to get on a train must underatke their lengthy journeys sitting and sleeping on the floor.

The situation with air transport is less dramatic, because most migrant workers can’t afford a plane ticket to return home. The mass migration, dubbed chunyun in Mandarin, starts two weeks before the official holiday and will last for 40 days.