This question was addressed a few years ago in this thread.
It’s also talked about a bit in the context of East and SE Asia in general in this thread
In general iNat is not very well known of popular in the region, even in countries where there aren’t access problems. There are a bunch of reasons for this, some cultural ones associated with people’s views of their relationship with the natural world, others economic (smartphones are certainly widely present, but they aren’t nearly as universally used in this part of the world as people Western countries tend to think they are), some of it has to do with work-life balances in these regions, there are often language barriers to use, and many other reasons. None of the reasons apply to all countries here, or even to all parts of large countries like China, but there are a lot of reasons behind iNat not being in common use.