"White" light sources are generally not really white. For example compared to sunlight ordinary light bulbs are a bit orange and fluorescent tubes have a green hue. Our brain mostly ignores these differences, but a camera sensor does not. The author might have turned up the saturation on these images though, I don't know how strong the difference is supposed to look.
Street lamps in NYC are mostly the old-school sodium lights still, which give the eerie yellow hue to the smaller side streets. I with that when they switch to LEDs that they keep that would keep that color (but they wont).
