With the start of the monsoon, there is a greater risk of growth of different bacteria and viruses due the favorable temperature for their breeding. So the outbreak of many infectious diseases through the polluted water like diarrhea, dysentery, cholera, typhoid, dengue and salmonellosis are common during the rainy season. The heavy rainfall causes the natural disaster like flood, landslides etc. which damages the water resources and pollutes the water by mixing of sewage, animal dung, human waste, chemicals etc. Generally, diseases do not generate itself, it is due to our fault and mistakes while using resources like water and food. So if we are little more conscious about such things then we will be safe. People throw sewage, garbage, and waste products into the river and people who are near the water resources misuse it. They wash clothes, throw waste product, mix animal dung, and pollute water resources. People are using chemicals on vegetables and crops and they are using old vehicles due to which they suffer from diseases like kidney failure, heart disease, and respiratory diseases. But in Kathmandu valley, people are compelled to use such polluted water due to unavailability of pure drinking water. So people here are suffering from different diseases which are caused due to polluted water, air, and food. The use of such polluted water for drinking, cooking, and other purposes cause adverse effects on our health. They may suffer from diarrhea, dysentery, cholera and others. So one must be very conscious about how to cure such infectious diseases. Many infectious diseases appear during the rainy season like diarrhea, typhoid, and cholera which are very common. Salmonellosis is the disease caused by the salmonella bacteria. People infected with salmonella develops diarrhea, fever, and vomiting as well as constipation which are caused due to consumption of polluted water and food. Another common disease during this season, especially in Terai region, is dengue fever which is caused due to a mosquito bite. Mosquito’s growth is very common in dirty water, damp and moist places. They can lay their eggs where water is collected. The growth of mosquito is very fast and it plays a major role in the transmission of other diseases. To prevent from such infectious diseases one should be aware to keep the surrounding clean and take care of personal health by the use of boiled water, wash hands with soap water, eat fresh and healthy food, protect oneself from mosquito bites by using mosquito nets.