One in five sailors in China's submarines in SCS suffer from mental health problems: Report China has been building military bases on artificial islands in the region also claimed by Brunei, Malaysia, the Philippines, Taiwan and Vietnam. Share Via Email | A+A A- By PTI BEIJING: One in five sailors serving with China's submarine force, especially nuclear subs in the disputed South China Sea, are experiencing mental health problems, according to a new research. China in recent years focussed its military deployment in the South China Sea (SCS), which has become a new theatre of conflict with frequent forays by US naval vessels to assert freedom of navigation in the region.