Polar Bear

Does this bear have access to anything natural? Sunlight, wind, grass, dirt? If not, this seems downright depressing!

No, this is it.

Hmmmm...perhaps a candidate for the 'Top 5 Worst Exhibits' list? Yikes...brutal conditions.

How old is this enclosure?

According to Wikipedia, Nanjing Underwater World opened in 1996 and according to an article I found from early 2007, linked below, the polar animals were added in 2007.
http://www.china.org.cn/english/environment/197654.htm

So I would say this is pretty shocking as the exhibit is actually pretty recent.

This is definitely up there with some of worst polar bear exhibits. I mean even the old concrete pit at Antwerp or some of the old-school grottoes were actually better than this awful concrete prison.