New Orleans has a much more prominent odor than NYC has ever had. It’s not just the tourist district, there’s a pervasive smell of sewage and rot. It merely recedes a little when the weather isn’t hot in wintertime.
I once traveled to NYC for photo shoots several times a year. That black runoff on seemingly all the streets has an odor when it’s wet, like garbage that hasn’t been picked up for too long. It’s more noticeable in the summer with the heat and humidity, not so noticeable when the weather is cooler and drier. From fall color to spring, if there’s a breeze and it’s dry, there’s no particular, generalized odor there, in my experience. That’s saying something, for such a very large city.
At least part of New Orleans is below sea level, if I recall correctly. That may have a lot to do with the odor. Most cities will have certain odors, just because of having so many people together and perhaps because of having so much concrete and asphalt.