Overview - Mustafah Abdulaziz for the Pulitzer Center on Crisis Reporting

Momoh, 33, collects plastic bottles from the polluted beach of Kroo Bay, a poor slum settlement of 5,500 people in Freetown, Sierra Leone. The cholera outbreak of 2012 struck hardest in the slums, where crowded and unsanitary living conditions and unsafe water sources allowed the disease to spread rapidly through the densely populated areas.

Freetown is a coastal city built for 600,000 and is occupied by nearly 2 million. The World Health Organization has reported 18,919 cases of cholera with 273 deaths since the beginning of 2012. International aid organizations have pressed for continued efforts to stabilize the spread while Sierra Leone’s government has declared a national emergency.

A man collects water from the polluted river running through the Grey Bush. The sources for water are limited and while international aid organizations have created temporary solutions in stand pipes, the issue of proper sanitation and water access has yet to be resolved.

Children in the Holy Trinity Primary School in east Freetown watch a cholera educational video from the Sierra Leone Red Cross Mobile Cinema Unit, which has toured the country in the aftermath of this year's cholera outbreak.

The Susan's Bay slum. In Freetown’s slums dripping standpipes are the major source of water. During the cholera outbreak, the clinic in one poor neighborhood called Susan’s Bay worked 24 hours per day. Patients came to the clinic for treatment but health workers also went out visit the homebound; the disabled, the elderly and people with HIV/AIDS.

Young girls are at the most risk for cholera, which is transmitted through water and food because they are typically responsible for collecting water for their families.

A public latrine in the Grey Bush. Open defecation is common while public bathrooms are generally in poor order and are costly to use. To use a toilet costs around 500 Leones, or $0.11 cents, which is striking when according to statistics from the World Bank the majority of the 6 million people live on less than $1.25 a day.

The Borborcombough Water Site in the Kroo Bay slum, one of two that service a population of 5,500 people. The Western Area — where Freetown is located — accounted for half of all cholera cases during the outbreak.

A boy washes in the second of two water points in Kroo Bay. The area is without access to clean water. Efforts to chlorinate these water points through the slum face behavioral challenges from the population: cholera and other water-borne diseases thrive in these conditions, chlorine in the wells degrades as they are used and the buckets used to retrieve the water are often dirty.

The main dumpsite in the center of Freetown where garbage and human waste has accumulated into massive caverns. While the cholera outbreak has receded by the end of the year, the danger for another remains.

Workers from Gee Fresh, one of the Freetown's main water bottling companies, sit in the back of a truck. Bottled water is often unaffordable to much of the population and the alternative are cheaper, smaller plastic bags of water.

The Guma Dam; the main supplier of water to Freetown is the Guma Valley Water Company. However, their pipes are crumbling and out-of-date and, despite a staggering three meters of annual rainfall, there is not enough water to go through the system. Any redirection to standpipes can cut off water from other sections. The company is entering into a 100-day plan for reform. It is unclear what the new plan will achieve.

The dumpsites used by government trucks and private companies reside within the city. In the center of Freetown is the Kingtom dumpsite in Grey Bush, a community of 12,000. It receives a large portion of the city’s garbage including human waste, which is then used by farmers to grow vegetables and provide income.

Young men stand in a wasteland burning garbage for copper. In the rainy season that stretches from May to December, shanty houses at the base are flooded with water and refuse. In the dry season, stagnant pools of water build up and are used as alternative sources of water to wash. Unsafe water sources and poor sanitation create a dangerous combination for waterborne diseases, like cholera, to spread rapidly.

The Western Area where Freetown is located accounted for 50 percent of all the cases in the outbreak. These slum settlements, strung out along the city’s bay, share a number of characteristics: extreme poverty, overcrowding, and unemployment. Homes are typically constructed of corrugated metal, possessing open dirt floors and makeshift roofs. Sources for water in the slums are consistently insufficient for the population

Fishermen drag in a net at Lumley Beach in west Freetown.

The polluted waters often bring small amounts of fish, tangled together with bottles and other trash.

Youths employed by Masada Energy to clean up the overflowing piles of garbage dump into a waterway running through the Kroo Bay slum of Freetown. Here, the young men spent one hour repeating this process before leaving for the day. Masada Energy recently received a new government contract to deal with Freetown's overwhelming sanitation problem.

Portrait of Ibrahim, 12, who burns for copper in the Ferry Junction dumpsite that receives a large portion of Freetown's waste.

A tourist from New Delhi floats in the clean water of River Number 2, a beach 16 kilometers south of Freetown and typically populated by tourists and aid workers.

A woman attempts to drink from a standpipe no longer in operation in Kroo Bay. Unsafe water sources and poor sanitation create a dangerous combination for waterborne diseases to spread rapidly.