How are open drains harmful to human health?, An open-drain is mostly used to collect wastewater that is not sewage. Use of open drains to dispose of sanitary waste is extremely unhygienic and unsafe. Use of open drains to a certain degree can be acceptable. However, any place with a collection of water breeds various disease-carrying pathogens., Open drains are harmful for human health as :, It is the breeding ground for flies, mosquitoes and many other disease-causing germs., It creates air pollution by its foul smell., During the rainy season these drains overflow and pollute the surroundings especially the water bodies and causes many water-borne diseases like diarrhoea, cholera etc.