Came in from Europe and De Blastio/Cuomo acerbated it.
Plus NYC inherently a cauldron for beewing up a big hotspot. Plus a decent chance that the NY strain via Italy was more virulent than the West Coast strain more directly from China. (That of course is cause for further speculation in its own right.)
Both guvs forced covid patients into nursing homes whoch presumably goosed numners in both states. Cuomo of course made HCQ hard to prescribe, don’t know about Newsom on that count.