The Historical Nawabi Pond is part of the water system that
supplied water from the fort to the town below. The water here is clean (as you'd expect), and the system appears to be operational. There's a pumping station in one of the towers next to the pond. The locals like to test their muscles trying to turn the iron wheel that forms part of the pump, but there's no chance of that working.
The pond is located in the Uparkot Fort complex and it's worth a detour as it's just after the entrance of the gates into the complex.