I was reading about the warring states period and some of the battles involved literally tens of thousands of people dying in them over the course of a couple of weeks.
Asia, especially India and China, always had much higher population numbers than the rest of the world. Around the year zero, Asia is estimated to have 141mil. inhabitants compared to 28mil. in Europe. That might partially explain the difference in numbers.
Also the geography of China with its central loam plateau might facilitate bigger armies as it is flat and fertile.
You should note that the battle you linked to, like many other in Chinese record, is for the entire campaign, not a single pitched battle.