With China, you’ll never know.
Hardly anyone has heard of the 1976 Tangshan Earthquake, yet it may very well be the worst natural disaster in history, with estimate of over a half million deaths.
China originally only acknowledged a few hundred deaths from that earthquake.
1931 China Flood 2.5 million-3.5 million
https://en.m.wikipedia.org/wiki/1931_China_floods
The worst 5 floods by death in history are all in China. Hard to believe the staggering death toll.