Increasing population and industrialization makes environmental damage inevitable, unless expensive and stringent safeguards are put in place. The Chinese government hasn't reached the point of caring enough to make that effort. The South China Sea provides a lot of food to the countries near it, and China, being the biggest, has the largest impact. To be fair, no government on the planet does all that it could to protect the environment, it's too costly.
For years, China and Japan have been far ahead of the Western society on the technological front. Unfortunately, China and America are both very uncaring with regards to pollution. China uses a lot of factories that in turn cause a lot of pollution. They should be making efforts to conserve the environment instead of destroying it.
Yes, China is causing damage in the South China Sea. Whenever humans interfere with the natural environment, there is at least some damage left behind. China has plans to float nuclear reactors in the South China Sea, and such a disruption to the environment would definitely cause a large amount of damage.
Yes, I believe that China is causing environmental damage in the South China Sea. Their manufacturing is not held to strict standards, and the pollution is awful. We all need to be concerned about this because the South China Sea is connected to other bodies of water. These problems can affect the world's water supply.