JUST as China is on its way up and many urbanites are prospering, there are many Chinese who seek greener pastures and green cards in Western countries. Yao Minji investigates and tells us why.

Sarah Lin, 35, quit her well-paying senior position with an international company six months ago to become a housewife and stay-at-home mom in a small town near Montreal, Canada.

It was a big step down for the former busy career woman who had been on the fast upward track in Shanghai.

But Lin adjusted her lifestyle and lowered her personal aspirations for what she strongly believes are in the best interests of her nine-year-old son who now attends primary school in West Montreal, a borough of Montreal, Quebec. More than a third of her son's classmates are also from the Chinese mainland.

"I miss my husband and my friends in Shanghai, but I'm getting to know the local Chinese community here, and I'll manage it - I have to, for the sake of my son," Lin tells Shanghai Daily.

Lin is not the only Chinese sitting in the yiminjian, or "immigration prison," as they call the long wait for legal residence status and later citizenship in countries like Canada, Australia, the UK, the US and Singapore.

Her husband remains in Shanghai, for now, working and sending money to his family.

He is reluctant to serve his "prison term" - immigrants are required to physically remain in their chosen countries for long periods before they are eligible for changed status. But he has found a Chinese agency to help him avoid the required stay and arrange to "make it work."

Lin's family and many others like hers are part of what experts and mainstream Chinese media are calling a "third immigration boom" from China to the West, following the first in the California Gold Rush of the mid-1800s, and second in the 1980s after the tumultuous "cultural revolution" (1966-76) and at the beginning of China's reform and opening up policy.

Reliable figures for Chinese "serving time" overseas are not available - at this time, many are still overseas on various visas, or have permanent residency.

But the trend of so called "elites" departing prosperous cities is evident and widely discussed. There are abundant examples of upwardly mobile people leaving China as it achieves unprecedented development and takes its place on the world stage.

Statistics from the Overseas Chinese Affairs Office of China's State Council (its cabinet) in June show that the total number of overseas Chinese has exceeded 45 million, largest of any nation.

Recent data from Australian Bureau of Statistics show that the number of immigrants from Chinese mainland has outnumbered that from New Zealand and India to become the highest of any nation (between August and October of 2009.) Statistics from the US and Canada also show an increase in applications for permanent residence by people from the Chinese mainland.

In response to the influx, Australia tightened immigration rules early this year and Canada is expected to follow soon - the closing window of opportunity has prompted those who were struggling with a decision to make the move overseas.

"The number of clients, especially those applying in the category of entrepreneurs, investors and self-employed, doubled last year. In 2004, we had only around 20 from both Beijing and Shanghai, but last year we had nearly 200, and many more inquired," says Donnie Liu, owner of a Shanghai-based immigration consultancy.

This third immigration (or emigration) boom has some features in common with the last one - those leaving China are the so-called elites.

They are mostly between 25 and 55 years old, well-educated and financially well-established. This group also has had some overseas experience, usually education and travel. And most important, its members have a single child on whom great hopes are pinned.

While many of their predecessors arrived illegally (many just overstaying visas), these people are buying their way to a good life overseas - by applying for visas and residence status as entrepreneurs.

This often requires they deposit a few million yuan into a state-owned bank, the national treasury or a company in their target country - to prove they are successful entrepreneurs who own at least one operating company back home. They also must provide financial statements to document their wealth.

Compared with other immigration categories overseas, this way is easier and faster, as long as people have the money and the financial documentation. The desire to move overseas is so great that many consulting agencies, like that of Donnie Liu, provide clients with all kinds of assistance in paperwork, arrange mock interviews to prep clients for tough questions, and some even deliver polished and virtually unassailable financial statements.

The process is tedious, and exhausting.

People must plan well ahead, as it takes at least a year, often around two years, to complete the process. A few million yuan must be placed in escrow accounts for three to five years, depending on target country requirements - with no earned interest.

Countries like the US may require applicants to start a company and hire 10 American employees.

Even after obtaining an entry visa and green card, one has to sit in the "immigration prison," often for three to five years, so as not to lose residency. For those with successful careers in China, this requirement is troublesome. But many people do it to provide what they believe to be a brighter future for their children.

"In China, there are two major concerns about children's growing environment - health and education," says history professor Gu Xiaoming from Fudan University.

"Considering all the negative news about food safety in recent years and the education system that also restricts students' intellectual growth, it is not surprising at all to see parents and parents-to-be trying to provide a safer and more promising environment for their kids."

Consultant Liu asks all clients why they want to move. The top three reasons are "good medical system, better education and good environment."

But Gu says parents should be aware that life in foreign countries is not as rosy as the pictures painted by immigration agencies. It's especially difficult for high-status Chinese to retain the same social status away from home.

This is probably why many immigrants try to avoid "immigration prison."

"For someone like me, who is used to metropolitan life in Shanghai, where all kinds of entertainment are just steps away from home, it is quite boring to live in a small town abroad," says Felix Zhang, a 32-year-old company owner whose application to Australia was turned down.

He is now applying for economic immigration to Canada with his wife and three-year-old daughter.

"I don't want to go and I can't just transfer my company there. But it makes me feel safer to have a green card or citizenship," says Zhang. "And it makes me feel like a good father to give my daughter a better starting point from the very beginning."