What is the 2016 South China Sea ruling over which China tried to bully Philippines?

The 2016 South China Sea arbitration ruling had declared China’s 'Nine-Dash Line' claim as legally invalid. The tribunal found that China encroached on the Philippines’ sovereign right by constructing artificial islands. China had declared the judgement "null and void". Notably, a Philippines minister has slammed China for handing him a note mid-speech explaining its position on South China Sea.