Before the rescue operation there existed a small basin called Khun Nam Nang Non but an entrance to Tham Sai Tong was opened to pump water out of Tham Luang for the search and rescue operation. As a result the pond became larger and deeper about 4 metres deep. When the water in the cave flows out the water containing limestone and other minerals reacts to turn the water emerald green. The water is not turbid but clear and pure creating an emerald pool.

Source: Site Visit