80-year-old Yu Zenghui has been preserving a wetland in north China's Tianjin after retirement, including building artificial lakes on bird islands and writing annals to make more learn about and protect the wetland.<br /><br />WATCH MORE: https://thestartv.com/c/news<br />SUBSCRIBE: https://cutt.ly/TheStar<br />LIKE: https://fb.com/TheStarOnline
