NYC has population fatality ratio of 0.17% to 0.23%. 8.4 million people and 14,753 confirmed COVID-19 deaths [0]. They have also 5,178 probable COVID-19 deaths. In other words, around 1 person per 500 overall died due COVID-19. Serology tests shows that only one in 5 people had the disease [1]. So the population fatality rate could still go up to 1 in 200. Imagine a wedding party, then imagine one person dead and 5 hospitalized, that's how bad it can get. There are very similar statistics in Bergamo, Italy and on board of Diamond Princess. Well, Diamond Process has infection fatality rate of 1.8% - 13 people out of 712 infected died.
[0] https://www1.nyc.gov/site/doh/covid/covid-19-data.page [1] https://www.nytimes.com/2020/04/23/nyregion/coronavirus-anti...