Not to discourage any other answers, but similar questions have been posed and answered before. On China, this thread, and this thread but this answer in particular by u/amp1212 would be helpful.

To note that last answer:

...but in the case of China you are mistaken-- there is far more historical material than you are aware of, probably significantly more than there is for Rome.

On India, there is this answer, probably more.

Hi there! You’ve asked a question along the lines of ‘why didn’t I learn about X’. We’re happy to let this question stand, but there are a variety of reasons why you may find it hard to get a good answer to this question on /r/AskHistorians.

Firstly, school curricula and how they are taught vary strongly between different countries and even different states. Additionally, how they are taught is often influenced by teachers having to compromise on how much time they can spend on any given topic. More information on your location and level of education might be helpful to answer this question.

Secondly, we have noticed that these questions are often phrased to be about people's individual experiences but what they are really about is why a certain event is more prominent in popular narratives of history than others.

Instead of asking "Why haven't I learned about event ...", consider asking "What importance do scholars assign to event ... in the context of such and such history?" The latter question is often closer to what people actually want to know and is more likely to get a good answer from an expert. If you intend to ask the 'What importance do scholars assign to event X' question instead, let us know and we'll remove this question.

Thank you!