When I began riding over 25 years ago, our tires weren't rated for that much pressure, usually more like 95 psi. They can be ridden at less pressure under emergency conditions, certainly better to ride home with low pressure than to walk.
I've ridden different brands of tires and tire sizes vary from brand to brand. The tires I bought back then that were called 700x25 actually measured 25mm wide. The tires I'm riding now are called 700x20 but they still measure 25mm wide. (I'm getting heavier though so I might need something a bit bigger now.)