Continuous rainfall and relatively high temperatures are the main reason behind recent reports of blue-green algae in some major lakes in eastern China, according to experts.

Blue-green algae recorded on July 1 near Bakou and Chuanchang, both on the eastern shore of Chaohu Lake in Anhui province, had increased by 852 percent and 479 percent respectively from levels reported last year, according to the provincial Environmental Protection Department.

Chaohu Lake is the country's fifth-largest freshwater lake.