One of the country's 10 largest freshwater lakes and the largest lake in Yunnan with a surface area of almost 300 square kilometers, Dianchi (滇池) has been under intense scrutiny by the country's environmental organizations since the 1990s.
The view from surrounding mountains of the once-glittering waters during sunset led to the lake's reputation as the pearl of the Yunnan-Guizhou Plateau.
It also supplied a substantial portion of Kunming's drinking water.
But contamination from industrial waste runoff, Kunming's sewage, and even an oil dump in 2006 from a boat that had been charged with cleaning up the lake have made the waters unfit for domestic or industrial use.
By 2020, more than RMB100 billion will have been invested into cleanup efforts of the lake, reported the China Daily.