This is the remains of what used to be the snow leopard enclosure before Roof of the World was built in 2005. This hasn't held any animals since.
Roof of the World was a Himalayan themed area with the aforementioned snow leopards, takin and red panda. The only part of it that remains today is the older part of the current snow leopard exhibit before it was extended.
@NMM Wow thank you, that does make some sense from the nature of the enclosure; although I don't suppose that fencing was used when it held Snow Leopards...
Whereabouts was the Red panda enclosure at Roof of the World?
While it's good that the Snow Leopard have more space, the extension is very poor imo. Just a big empty space, completely incongruous with the (excellent) original enclosure, with terrible viewing (was that awful fencing going cheap or something - looks like it was meant to have windows?).