He's talking about implementing government-run grocery stores. I don't think that's a good idea.
https://reason.com/2025/10/30/3-reasons-why-zohran-mamdanis-city-run-grocery-stores-will-fail/
New York already has a lot of grocery stores. If those grocery stores are too expensive for people, a better idea would be to rewrite zoning laws so that supermarkets (like Wal-Mart, for example) could be built in New York City.