Concerns arose on Chinese social media after reports surfaced that approximately 7 metric tons of bleaching powder would be applied to West Lake in Hangzhou, Zhejiang province, prompting clarification from officials that the treatment is an established part of annual maintenance aimed at protecting the lake’s lotus plants.

The West Lake water area administration confirmed the operation is routine, designed to safeguard lotus flowers during their critical growth phase in April. Officials explained that increasing spring temperatures lead to the proliferation of pests, pathogens, and algae such as spirogyra, which compete with lotus plants for nutrients and can damage delicate new shoots. Herbivorous fish also pose a threat by feeding on the emerging buds, potentially causing rhizome rot and preventing blooms for the entire year.

The disinfectant used in the treatment primarily consists of calcium hypochlorite. Authorities emphasized that it is a regulated substance known to eliminate harmful organisms and suppress algae growth before naturally decomposing within one to two days. The 7,000 kilograms of bleaching powder referenced will not be applied at once but will be dispersed incrementally across 24 designated lotus zones covering about 10 hectares.

To reduce impact on visitors and wildlife, the disinfection process is conducted overnight and follows strict protocols. Workers operate in pairs by boat, starting from the edges of enclosed treatment areas to ensure even distribution and containment of the chemical. Protective nets isolate the lotus planting zones, which account for roughly 1 percent of the total lake surface. Prior to treatment, the nets’ bottoms are lifted to allow fish to leave the zones, minimizing exposure and preventing fish from grazing on the shoots afterward.

Officials maintained that the use of bleaching powder during this operation has minimal environmental impact on native fish and bird species and is carried out in an environmentally safe manner. The overall maintenance of West Lake is a year-round effort, including reinforcing nets in spring, weeding and thinning plants in summer, installing enclosure nets in autumn to aid root nutrient storage, and clearing withered plants during winter to prepare for the following growth cycle.

This year’s disinfection work began on Wednesday night and is expected to be completed by Sunday. Following the operation, lotus buds should gradually appear, with the first flowers forecast to bloom by late May. In addition, authorities have introduced a long-flowering autumn lotus variety on a trial basis in the Fengyu Pavilion area, which is expected to extend the lotus viewing season to November.