One loving Chinese mother has moved around several times in the past few years, trying to find a clean place for her son who suffers from severe asthma.

Chinese premier's visit to Pakistan underlines two countries' mutual desire to push forward increased cooperation in various fields.
China may start levying taxes on an increasing number of luxury goods as part of the country's efforts to push forward economic reform.
China will never pursue temporary economic growth at the expense of environmental degradation, President Xi Jinping vowed on Friday.
Ecuadorian President Rafael Correa took office on Friday for a third term with a promise to eradicate poverty and reduce social inequality.
Emergency disaster relief responses were initiated on Friday as heavy rain continued to batter many parts of the country.
Yang Jiang, late Chinese writer Qian Zhongshu's wife, says it is "very inappropriate" to publicize the family's private communications.
Two years on, little has changed with sixth-ranked Li Na being the only Asian player ranked inside the woman's global top 30.