My guess is COVID spread in NYC from ventilation systems, elevators and the subway. But the City would die without the subway. The folks who work at restaurants, Gristedes or Whole Foods in Manhattan all live out in Queens or the Bronx. You close the subway, nothing could open. You'd have starved the place out in a week. The places in NYC are tiny and no one had a week's worth of food sitting in their pantries.
I've lived in NYC and Tokyo. The commuter trains from the suburbs into Tokyo and the central business district city trains make NYC look like rural Iowa by comparison in terms of crowding. I was in Tokyo when SARS 1 hit. There wasn't a single person on those trains without a mask. Even during COVID, the guys I have talked to still went to work and said the trains were at 75% capacity. The entire metro Tokyo area (which is probably over 25 million people) has under 8,000 cases. Now part of that is the government has stopped testing unless they think you are going to need medical attention but they have realized it is pointless to test some healthy 22 year old guy to see if he has rony because it ain't gonna kill him. They say "assume you have it, assume everyone else has it, act accordingly." They have under 600 deaths in Japan.