With a name evoking another era, the blue sheets of metal also tell a tale of China's growth — and of the steep bills coming due.
They call it the "Blue Great Wall."
The cobalt-hued metal sheets sprang up just weeks ago across Tianjin, a port city of over 15 million people in northeastern China. They crisscrossed streets and alleyways. They cut off businesses from their customers. They separated neighbour from neighbour.
"From this day forward," read the signs affixed to many of them, "this residential community will be managed in a closed-off way."
Barriers of all kinds have sprung up across China. The country is battling the outbreak of a disease called COVID-19, which has killed more than 3,200 people and sickened tens of thousands more. It is caused by a new coronavirus, so named for the spiky protrusions that cover its microscopic surface.
To stop the coronavirus from spreading further, the Chinese government is thinking up new ways to separate its people. Traveling between many of its cities has ground to a virtual halt, freezing large swaths of the world's second largest economy.
The Chinese Communist Party has spent decades pressuring and cajoling a historically fractious nation of 1.4 billion people to see China as a united country. Now, it is keeping them apart.
Barriers have risen up at the neighbourhood level too. Guards now surround many residential complexes. In some places, only one member of a household can leave home at a time to go grocery shopping or just get a breath of fresh air.
Some places, like Tianjin, have erected walls around entire neighbourhoods. Officials in those places have discovered that metal sheets, the type typically used to keep people from wandering onto construction sites, make handy walls.
China has plenty of those types of sheets lying around. For years, the country has turbocharged its economic growth by building. Office complexes, highways, airports, shopping malls, steel mills — some barely used — stand as monuments to a single-minded devotion to growth.
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To fuel that growth, local governments and government-controlled companies borrowed money from the country's state-run financial system. Now, China's economic growth is slowing — a phenomenon that predates the coronavirus outbreak — and the local debt load across the country is estimated to total in the trillions of dollars.
Perhaps no place in China embodies that mindset more than Tianjin.
Tianjin was long one of the fastest growing places in the country. It got there by introducing ambitious plans to build industrial parks, economic zones and glamorous skyscrapers, some among the tallest in the world. One glassy district promotes itself as China's Manhattan.
Now the bill is coming due. Tianjin officials recently admitted they overstated growth, and it is now one of China's worst performing cities. Many of its construction sites had gone idle. Experts estimate its debt load totals hundreds of billions of dollars.
When the coronavirus struck, local officials sprang into action. The district of Heping in particular seized on the city's huge supply of blue-coloured construction walls as a way to stop the virus's spread. It helps that Tianjin neighbours Hebei province, an industrial area where steel mills are plentiful and supplies can be easily found.
Heping officials called the steel sheets the "Blue Great Wall," though it is in fact a series of smaller walls across the district. The name is a reference to the Great Wall, which China's imperial leaders built to ward off northern nomads in another era. Though it did not end up helping much, it symbolises national determination.
The local government said in a statement that the Blue Great Wall blocks off side entrances into communities and lets officials more easily track people moving through main entrances.
"The Heping district manages and controls complex entrances to block any unnecessary access into a community and maintains only a main entrance, building a 'Blue Great Wall' of security," a statement from the district government said.
The local government-controlled news media has reported that residents feel more at ease now that the Blue Great Wall has been erected. But it has also reported that people have found gaps and bent the walls in places to more easily get through. Like its inspiration, the Blue Great Wall ultimately cannot stop human nature.
Written by: Cao Li
Photographs by: Yuyang Liu
© 2020 THE NEW YORK TIMES