If there is active fighting over the city, whoever controls the main train station (or, if destroyed, the piece of ground where the train station used to be) is counted as controlling the city.
This is question #3 in the Astral Codex Ten 2023 Prediction Contest. The contest rules and full list of questions are available here. Market will resolve according to Scott Alexander’s judgment, as given through future posts on Astral Codex Ten.
This spent a bunch of time near 50% in early January, then went down. Once again Metaculus has been consistently lower and it is down at 13%. That feels very low, I’d probably be closer to 20% although I am doing much less work keeping up with the war these days, but 28% is a lot given how things are progressing right now. I bought M250 of NO shares, driving the price to 25%.