Participants from the various provinces and regions who head to Tibet as part of the aid program can suffer profound culture shock, said Wu Haifeng, 39, a general practitioner from Heilongjiang province.

One day in a sickroom of the county hospital in Xigaze prefecture where he worked, Wu swatted a fly with a newspaper roll.

The doctor thought nothing of the act but he soon found local Tibetans staring at him in horror.

"Everyone stopped talking and looked at me. The air itself seemed to have frozen," Wu said.

"A woman started to pray."

As devout Buddhists, Tibetan residents do not kill flies.

"But as a doctor, killing flies in the sickroom is almost an instinct," Wu said.

"But I had to respect the local religion and learn to chase the flies away instead. That was the least of what I could do in front of the locals."

In the county hospital, which has 70 sickbeds, the smell of buttered tea filled the air. Wu said many patients used to make fires to boil their traditional drink in the sickrooms.

"It is their tradition to make fire indoors. We can't say 'no', although it is a big fire hazard," Wu said.

"We need to respect their lifestyle and habits. So instead of saying 'no', we built a teahouse next to our hospital building."

People who work in the region must learn Tibetan language and history, the doctor said. After one and a half years living in Xigaze, Wu is able to greet people in Tibetan and carry out simple conversations with his patients.

"But most times I need my student to be my translator and we learn from each other," he said.

"After you get to know the local culture, you will find it fascinating. After I leave, I will always miss my experience in Tibet."