Tensions in the South China Sea have escalated in recent months as the Philippines ramps up incursions into China's territorial waters. But one underreported issue is the environmental impact of Manila's actions. New research shows that the Filipino vessel, which has been illegally grounded at Ren'ai Jiao, or Ren'ai Reef since 1999, is contributing to the destruction of the marine environment. CGTN reporter Yang Jinghao has been on a journey through the waters and has this exclusive report.