This question resolves to "Yes" if the population of China is less than 700 million people by the end of 2029. Otherwise "No".
If official sources and unofficial sources of population numbers disagree across the 700M threshold then the question will resolve based on weighted repute of estimates, with a bias towards real money prediction markets that attempt the question.
If China's population changes significantly based on gaining or losing territory, resolution will be based on the borders extant on 1 November 2022. For example, if China takes Taiwan or India, those populations don't count towards resolution, but if China breaks up into 3 sub-states then their populations are added for resolution. The question is focused on the population inhabiting the 2022 borders, currently officially 1.412 B (World Bank)
The "Public Predictions" series captures interesting predictions made publicly by relevant experts. This prediction: https://youtu.be/tjYDcuOlK_M