In Kaifeng city, known as one of the main cradles of more than 2,700 years of Chinese history, a new night-time tradition has taken root in recent months. 

Thousands of cyclists have been gathering to pedal through Kaifeng's winding streets, their bikes cutting paths through the historic city, lit by street lamps and the glow from smartphones.

But the overwhelming popularity of the cheap activity, which has taken root as young people face the prospect of bearing the brunt of China's economic woes, has prompted a clampdown as main roads have been overrun with cyclists.

The pilgrimage started back in June, when a handful of female students decided to take advantage of the warm evening weather to cycle more than 50 kilometres from Henan's provincial capital Zhengzhou to Kaifeng – one of China's ancient capitals – for nourishing soup dumplings. 

By this weekend, tens of thousands were taking part, clogging a main arterial highway between the two cities and causing traffic chaos.

Some participants have referred to it as the "Night Riding Army", with many hiring share bikes for as little as $3 per month.

One participant, 20-year-old Xia Tian, summed up the allure: "I've been feeling a bit down and anxious lately, and when I saw a night cycling event, it looked so spirited and free.

"I decided to tell my friend and join in and unwind.

The trend has drawn residents young and old, locals and visitors, looking for a brief escape from the daily grind. 

Chinese state media reported that people online were jokingly calling the pilgrimage the "great migration of shared bikes" and "Zhengzhou students' night raid on Kaifeng". 

Another college student, Parus, posted on her Xiaohongshu account – China's answer to Instagram – that people had given them gifts and food along the way. 

"Went on an impromptu trip with classmates! A big group set off from the city sports centre," she posted.

"We received all kinds of supplies – bottled water, snacks and even Snow Beer.

"When we arrived in Kaifeng, it was really late, so we ordered milk tea and xiaolongbao ... enjoyed them right at the Kaifeng city gates — it was perfect! … Life experience +1!"

The cycling trend has been a rare eruption of joy and spontaneity, as China continues to struggle through an economic crisis that has seen record low youth unemployment and caused confidence among Chinese consumers to plummet.

Earlier this month, the Kaifeng Cultural and Tourism Bureau issued a "Cycling to Kaifeng Initiative", welcoming young riders to the city.

Pan Wang, associate professor in Chinese and Asian studies at UNSW, said young people were participating in the phenomenon for a variety of reasons, to have fun or because they loved soup dumplings while some were just blindly following a trend.

"Social media here plays a key role in this mass mobilisation," she said.

"I guess this is an emerging youth culture led by university students. 

"It is collective but not political — but it potentially could lead to something concerning.

"For students this year, they just want to maximise their youth time by doing the things that they feel like doing at any time — pursuing their passion and so — and then that triggered more and more students who want to get involved in that."

Looking to cash in, several tourist attractions announced free entry for those taking part, and local authorities set up bike drop-off points along the route with volunteers providing water and assistance.

But as the trend grew, several tourist attractions in Kaifeng reached capacity limits, according to local media

Universities in Henan called for students not to take part, saying that "while youth is full of energy, safety should always come first", according to Chinese media outlet Phoenix Television.

Authorities initially welcomed the wholesome revelry, but concerns grew as the sheer number of participants caused traffic chaos and safety concerns.

On Friday night, a particularly massive turnout prompted a reaction with the number of participants reportedly reaching over 100,000.  

An online statement from the provincial police on Saturday said the road would be closed to non-motorised vehicles from 4pm to midday on Sunday "due to its occupation by shared bikes and other objects at various points".

Several share bike-sharing companies urged the college students to limit their rides over safety concerns and warned their vehicles would lock down if ridden out of a designated zone.

Some riders reported that their rented bikes automatically locked, requiring a "dispatch fee" to release them.

In a statement, the Kaifeng city government warned of the the risk of riders falling and sustaining injuries, or blocking other road users from accessing medical care.

"[You] have demonstrated the wilful whimsy of youth," it said, "but … more and more people are starting to worry about the hidden dangers."

One news outlet admonished in a comment piece: "Youthful freedom does not mean following the trend and indulging oneself." 

"Kaifeng is worth arriving slowly and savouring carefully," read the headline of another.

ABC/wires