The northern end of the lake is called Caohai (Chinese: 草海; pinyin: Cáohǎi) and has a surface area of 7.5 km2 and an average depth of 2.5 meters.

Modern studies suggest that the character 滇 is derived from the language of the extinct ancient Bo people and means basin.

[4] The character 滇 has been used as the name of the lake since at least 109 BC, when the Han dynasty established "Dianchi County" (滇池县) in the area.

100,000 soldiers along with students and factory workers were mobilized to "fight a war of annihilation to take farmland from Dian Lake".

Immediately after taking office, Tan Furen announced that Dian Lake would be a model for the national "reclaiming land from the sea" campaign.

Yunnan Province has long been primarily agricultural, but the Dianchi basin has witnessed high industrial growth and boasts the highest population density within Kunming City.

[9] The pollution peaked in 2009, at which time the water in Dian Lake was classified "worse than Grade 5" (too dangerous for human contact).

[14] As a result, some wetland parks have been constructed in the lakeside zone to purify the water and create leisure areas for citizens.

They are small water bodies with aquatic plants such as Phragmites australis, Typha orientalis, Acorus calamus, Eichhornia crassipes, Lemna minor, and Pistia stratiotes;[8] outside the ponds, there are trails, trees, and lawns.

[16] Of the 25 native fish species and subspecies in Dian Lake, 10 are endemic to the basin: Acheilognathus elongatus, Anabarilius alburnops, Anabarilius polylepis, Cyprinus micristius, Liobagrus kingi, Pseudobagrus medianalis, Silurus mento, Sinocyclocheilus grahami, Sphaerophysa dianchiensis and Xenocypris yunnanensis.

[16][18] Two other species, Schizothorax grahami and Yunnanilus nigromaculatus, are endemic to the general region, but have also disappeared from Dian Lake itself.