THEY FUELED their nation鈥檚 dramatic economic rise, toiling in jobs far from home, but China鈥檚 migrant workers are now finding themselves increasingly unwelcome as authorities try to cap the population explosions in key cities.

Lin Huiqing moved to Beijing to look for work when his children were still in diapers.

For the last 18 years, he has seen his family just once a year, the rest spent doing the hard labor most Beijingers would prefer to avoid.

The 50-year-old is one of hundreds of millions of migrants who moved from the countryside to the cities, a colossal demographic shift that made China鈥檚 ascent possible.

But last month Lin was evicted from the village where he lived on the capital鈥檚 outskirts, another victim of a city-wide demolition plan to limit Beijing鈥檚 population to 23 million by 2020 鈥 a target that could come at the cost of its economy.

鈥淚f I go home, I have no way to support my wife and kids,鈥 Lin lamented.

According to the Communist Party mouthpiece People鈥檚 Daily, the city plans to demolish 40 million square metres of 鈥渋llegal鈥 structures.

Many are the homes and shops of low-income migrants like Lin.

When he first arrived in Beijing, Lin and his friends pooled their money and took out loans to purchase delivery trucks.

He made a living hauling the wares of small-scale shopkeepers and traders, but the moving business has taken a hit as the city condemns buildings en masse, evicting tens of thousands into the winter cold.

鈥淥ur customers are commoners like us,鈥 he said. 鈥淲ith their small businesses shut down, there鈥檚 no stock for us to move. We鈥檙e basically unemployed now.鈥

Authorities say the campaign, which kicked into high gear after a fire in an illegal structure killed 19 in November, is needed to clean the city up once and for all.

But it is also removing vibrant chunks of Beijing鈥檚 economy, such as retail and small scale manufacturing, and throwing into chaos other sectors like delivery, the bedrock of the booming e-commerce trade.

Relegated to the periphery, migrants have kept China鈥檚 economy humming, handling the difficult, dirty and sometimes dangerous work that the city鈥檚 permanent residents won鈥檛 do.

Urban industries like construction, domestic work and sanitation are almost completely staffed by migrants.

Eli Friedman, associate professor of international and comparative labor at Cornell University, said China鈥檚 biggest cities 鈥渟imply cannot function without migrant workers.鈥

鈥淚f every non-local were to actually be removed from cities like Beijing, Shanghai, and Guangzhou, these economic engines for the whole country would completely collapse,鈥 he told AFP.

But that is exactly what is happening, said Li Ning, one of the 60,000 delivery drivers who criss-cross Beijing鈥檚 streets.

Li was recently evicted from a village on the city鈥檚 outskirts, forcing him into an apartment where the rent quadrupled.

Then authorities came for his delivery company鈥檚 warehouse, forcing staff to sort packages on the sidewalk and sending his income plummeting.

鈥淚n Beijing all the migrants are leaving. We can鈥檛 make it here anymore,鈥 he said, adding he plans to leave for good during the upcoming spring festival.

Another delivery franchise owner surnamed Wang said she will 鈥済ive up鈥 if authorities knock down her current warehouse, which they marked in black paint with the character 鈥渃hai鈥 鈥 (demolish) 鈥 in mid-December.

She had just moved in Dec. 1, after she had to close two other delivery hubs this year, forcing her to cut her work force from 240 couriers to 60.

鈥淭here鈥檚 no stability. I don鈥檛 know what I鈥檒l be facing tomorrow,鈥 she said, tears welling in her eyes.

The demolitions have also hit Beijing鈥檚 retail sector, decimating once affordable mom and pop shops and pushing consumers online or into high-end malls.

Two years ago, Ge Guoxiang moved with his wife from their home province of Jiangsu to take over his brother鈥檚 textiles stall.

It had thrived for over 20 years in Beijing鈥檚 Tuanjiehu Tianyu market. But three months ago, they received notice that authorities will shutter the market.

Dozens of small-scale community markets have been forced to shut down this year 鈥 including the iconic Beijing Zoo market, where hundreds of merchants organized rare street protests against the evictions.

Officials said they have designated certain areas in the neighboring Hebei province where merchants can move their businesses to.

But Ge is unconvinced.

鈥淚t takes years for businesses like ours to build up clientele. Now we have to start over,鈥 he said.

鈥淥ur clients are mostly older people who don鈥檛 know how to shop online. Where will they go?鈥 鈥 AFP