I just came back from 2 week CNY trip to rural mountain village in Baoshan, and I think that the situation is much worse in places like that, than in Kunming, Dali, or other developed cities.
They don't have incinerators in range, nor is the small reward for taking bottles to nearest town for recycling a viable option for most households, even those impoverished. Or especially them, since they rarely have even vehicles to do the trip.
It's a long haul down the mountainside to nearest waterway, but that's where the discarded plastic ends up eventually anyway - there's no escaping gravity.
And by the time it does get to the river and starts floating toward Lancang, much of it will have eroded into microplastics that cannot be caught by most mechanic filters like these nets in Australia.
I think that the state and local governments should step up there, and arrange scheduled trash collection tours to mountain roads. They could employ locals for financial income, while at same time raising awareness for proper handling of trash.