The people of Mariupol have suffered unimaginably in the past few months, but their suffering is unfortunately far from over. The city mayor said that after months of Russian siege and attack, the drinking water is now contaminated by corpses and garbage, raising the threat of cholera — a bacterial disease that usually spreads through contaminated water.

Four months ago, Mariupol was a normal, thriving port city in Ukraine. Then, Russia attacked. The Russian military considered it a strategically important point for their invasion of Ukraine and for weeks and months, they bombed and sieged it. Most of the city, which had 430,000 people before the attack, was reduced to rubble — according to Ukrainian authorities, around 95% of the city was destroyed by Russian bombardments. Some 150,000 people remain in the city now, with city officials claiming that over 21,000 civilians were killed. For the people that survived in Mariupol, it’s one humanitarian crisis after the other.

The Red Cross described the situation as “apocalyptic”, and as Russian forces gradually seized control of the city, things are only getting worse. In March, Petro Andryushchenko, advisor to the mayor of Mariupol, reported that people were “drinking from puddles in the streets” due to the loss of running water in the city. People in Mariupol are routinely cooking food on fire outside apartment blocks, and much of the city doesn’t have access to drinking water.

It’s hard to say just how bad the situation is in the city now because Russian forces prevent communication from Mariupol, but residents have told media that corpses and rubble litter the streets.

According to a report from the World Health Organization, the lack of drinkable water and the destruction of sanitation systems can pave the way for infectious diseases to emerge in Mariupol, including cholera. Ukraine was the last European country to declare a cholera epidemic, with 33 cases in 2011 in Mariupol — which has doctors worried that a new cholera outbreak. Last month, Dorit Nitzan, the WHO’s Ukraine incident manager, said that Mariupol now has “actual swamps in the streets,” and sewage water is getting mixed with drinking water. Without water, people have taken to drinking water from rivers and lakes. “This is a huge hazard for many infections, including cholera,” she said. Russian forces aren’t allowing WHO or other international organizations access to monitor and help the situation.

The situation is further amplified by the situation in Mariupol hospitals, which Andriushchenko says is “catastrophic.” “Visual demonstration of complete paralysis and collapse of [the] medical system… In this state of medicine, any infectious disease turns into a deadly epidemic,” the mayor said on his official Telegram channel.

Indiscriminate bombing, sieging, and destruction have brought Mariupol to disaster — and now, infectious diseases are at an arm’s length. The last thing Ukraine needs is an infectious disease. Hopefully, it doesn’t happen.