Surface and pitting corrosion in a water pipe

A decades-old water pipe made of hot-dip galvanized construction steel is massively corroded inside, with numerous wall penetrations. The zinc coating on the inside has been eroded for a long time. On the outside, remnants of the zinc coating remain, albeit slightly corroded on the surface and already full of cracks. On the outside is the pure zinc layer (light-colored), and below it the intermetallic iron-zinc compound layer (brownish with a faintly discernible stalk-like structure).