I live in Anderston so I know a little bit.
Right by the bridge there was a fire at a factory so that accounts for some of it (cheapside street I think). The rest would have just can industrial buildings that fell out of use when industry collapsed and there wasn't enough money at the time to preserve it.
I know it wasn't all industrial buildings as there were tennemants round there in old photos I've seen. The photos show an area in a pretty bad state so I would assume that would have just been torn down in "slum clearances". Most people would have been moved to tower blocks and new towns. Those are now being torn down so in the long run it would have probably been cheaper to just renovate the tennemants.
Edit: this is what it used to look like http://www.mitchelllibrary.org/virtualmitchell/image.php?i=13566&r=2&t=4&x=1 |