Class iii and above. Through comprehensive management and ecological restoration, the pollution load of Nanwan Reservoir has been effectively reduced, and the water quality has been stable at Class III and above in surface water all the year round. Nanwan Lake is located 5 kilometers southwest of Xinyang City, Henan Province, with Nanwan Lake as the center and mountains and islands as the scenic connotation. The water area of Nanwan Lake is 75 square kilometers, and 6/kloc-0 islands (three of which are now open) are scattered and have different scenery. The upstream of the lake is the main producing area of Xinyang Maojian tea, and the lake is rich in South Bay fish.