#1. Port Harcourt, Nigeria. Due to sewage treatment issues rivers of Nigeria are highly polluted. The residents of Port Harcourt suffer the most. The situation is aggravated by crude oil extraction. Plenty of oil spills caused by the use of outdated equipment remain untreated for years.

#24. New Delhi, India. Anything but fish could be found in the Yamuna River that crosses the city. Industrial and municipal waste is dumped in the river without any treatment. Besides that, the river works as a cemetery and a scrapyard for the local poor. The only living creatures that are happy with the current situation are bacteria that cause severe water-borne diseases. This is why New Delhi holds the leadership among Indian cities in childhood and infantry mortality rates.

#23. Maputo, Mozambique. This country is situated on the shores of Indian Ocean that suffers the most of careless activities of the locals. Municipal waste and wastewaters are discharged to water without any treatment. No water treatment plants were built so far in country's capital or in other cities. Streets are flooded with trash. The Temb River that crosses Maputo has become a stream of sewage.

#22. Luanda, Angola. It is the largest city and capital of Angola, located on the shores of Atlantic Ocean. Latest researches revealed poor quality of tap water. Part of the population inhabits musseques – barracks made of trash and on trash. There is no plumbing system in these districts, and local residents obtain water from huge barrels transported to their dwellings. Concentration of chlorine and chlorine-organic substances in this water is incredibly high, but so far it's the only way to prevent cholera outbreaks.

#21. Niamey, Niger. The Niger River that crosses the capital of the country is a cesspit because of dumping of municipal, industrial and agricultural wastewaters along with garbage. Average life expectancy in the city is 35 years for men and 36 years for women. The reason is in morbid quality of tap water and the lack of adequate sanitation. This costs a life to every fourth child in the city younger than five years.

#18: Lomé, Togo. The capital of the country is located in the south west, near Ghana border. The main problems of the city are waste management and treatment of wastewaters. Most population of the capital city doesn't have an access to safe drinking water and sanitation. Seasonal flooding makes the situation even worse.

#17. Pointe-Noire and #10. Brazzaville, Kongo. Air pollution, shortages of drinking water and pollution of the main water source due to dumping of untreated wastewater are the reasons why these two cities were named by experts among the dirtiest in the world. By the way, 70% of Kongo population inhabits these two cities and small villages along the railroad that connects them.

#6. Addis Ababa, Ethiopia. Country's capital population faces the gravest problems with sanitation in Africa and in the world. Water-borne diseases spread very quickly, resulting in high childhood and infantry mortality rates and low life expectancy.

#4: Port-au-Prince, Haiti. Both air and water are polluted and dangerous. Lack of ecological control already resulted in irreversible environmental changes on the island.

#2. Dhaka, Bangladesh. Residents of the capital city fight water-borne diseases. All surface water sources are contaminated with bacteria and polluted with pesticides that are vastly used in local farming. Over 150 million people are cramped on a relatively small territory, that results in even worse problems of water treatment.