One loving Chinese mother moved around the country several times in the past few years, in order to find a clean place for her son who suffers from severe asthma. In the end, she decided to send her boy off to London.

Shang Yujun used to be a popular doctor in Changsha, capital of Hunan Province in central China. Her son Tian Tian was born in June of 1992. "Tian" means "sky" in Chinese, expressing the parents' hopes for their child to have a bright future.

Unfortunately, good times don't, and in this case didn't, last long. Tian Tian suffered from acute asthma when he was two years old. He was diagnosed with exercise-induced asthma, possibly relating to an allergic reaction. Nevertheless, after all available examinations had been done, doctors still failed to determine the source for the allergy.

"This can only be about the air," said doctors. They suggested the parents reduce the boy's outdoor activities to protect him from getting a cold and even change his living environment if necessary.

Changsha's air quality was not good in the early 1990s. With pharmaceutical and chemical factories built within the range of some ten kilometers from the city, the polluted air was unavoidable -- even though the family lived in a comparatively closed-off military compound.

As a young naughty boy locked inside the house, Tian Tian could hardly contain himself from jumping, laughing and crying, which often led to asthmatic relapses. A doctor herself, Shang feared that her son's asthma might develop into chronic bronchitis and emphysema.

The constant worrying unexpectedly came to a halt when Tian Tian was four years old. In the winter of 1996, his father was transferred to a post in Shenyang, capital of Liaoning Province in northeastern China, in cooperation with an American company. The whole family moved to the city and was assigned to live in a well-afforested, environment-friendly area designed by American entrepreneurs.

They spent two years in Shenyang, a time during which Tian Tian's condition took a turn for the better. His parents were deeply impressed by the Western idea of environment-friendly architectural design. Upon completion of his father's working contract, Tian Tian had reached school-age.

Instead of returning to Changsha, his parents opted for Guangzhou, capital of Guangdong Province in southern China, as their next destination as it was comparatively clean. There, Tian Tian spent his primary and middle school years.

Throughout these ten-odd years, his parents took any possible opportunity -- school vacations and business trips -- to take their son abroad. They had been to Australia, New Zealand and many European countries. Whenever they stayed in a clean, beautiful place, Tian Tian's cough, colds and sore throat would "magically" disappear.

From 2004 to 2008, Guangzhou witnessed severe mist weather and river pollution. The area's drinking water became the most worrisome problem for citizens. Tian Tian suffered from severe coughing spells as well as a sore throat and his overall health was very unstable.

In September 2009, the Guangzhou city government announced that a large-scale garbage-burning plant would be built within the city. This final straw pushed Tian Tian's parents to send their son abroad.

In May 2010, Tian Tian passed his AS exams and in August of 2011, he got admitted to University College London (UCL). Soon he left for London and began his college studies, majoring in British civil engineering.

During the London mayor election campaign of 2012, candidate Boris Johnson opened a Sina.com blog to get feedback -- and votes -- from foreign students' parents, including Tian Tian's mother.

Knowing that Mr. Johnson held an intense interest in environmental protection, Tian Tian's mother wrote on her own blog, "When Tian Tian was at home, I used to worry about his food and beverages, let alone the air. Now, I don't have to [anymore]. As a mother, I must find the best way to protect my son."