The highly toxic disinfectant sodium hypochlorite may cause poisoning and even death. Due to chlorine gas emission, entry of this toxic substance into the environment might hazard the environment. To combat the COVID-19 pandemic, various disinfectants were utilized by various countries. Likewise, the substance was extensively used in Iran to deter the disease and consequently large amounts of chlorine were released into the environment which may have affected the environment and disrupted the natural balance of ecosystems possibly causing irrecoverable damage. Sampling of larval habitats was conducted in a standardized way in March 2020 in two cities of Abadan and Khorramshahr in Iran in order to investigate the effect of sodium hypochlorite on the mosquitos’ population during the fight against COVID-19. The data were compared with that of conducted in March 2019. The results showed that a total of 1887 mosquitoes were caught in March 2019, including Culex, Aedes and Anopheles, while after the bleach entered the larval habitats, only 180 mosquitoes of the genus Culex and Aedes have been caught; while, no Anopheles was caught. By comparing climate data for March 2019 and 2020, it can be concluded that the most important factor influencing the reduced population of mosquitoes in larval habitats is associated with the entry of the bleach inside the relevant environment. This study attempts to identify the risks of human interference with the excessive consumption of disinfectants.