Via heroic shutdown measures (basically, confining most of the population of this huge city to their apartments), the Chinese cut the R0 in Wuhan by more than an order of magnitude down to 0.32. New infections fell by almost 95%.
Granted, there is the important question of how much to trust Chinese statistics. I can’t answer that, but it’s worth pointing out that China’s boss, Xi Jinping, had been keeping himself far away from Wuhan. Xi is an ambitious man who wants to be ruler of China for decades into the future, so he’d only sent disposable deputies. But on Tuesday, it was reported that he was paying his first visit to the plague spot, suggesting that the situation had indeed improved enough for Xi to risk his own health.
This, in large part, explains Trump's decision to shut down travel from the EU to the US for one month. Also, Italy has closed down all markets except groceries and pharmacies. Taking such drastic measures today gives us the best chance of conquering the Coronavirus.