In just under a fortnight, leaders from some of the world's major economies will gather in South Africa's economic heartland, Johannesburg, for the G20 summit.

But just a few kilometers from the spruced-up, highly secure venue is a city center which the authorities are struggling to improve and keep safe.

They face major challenges in cleaning up more than 100 derelict buildings, many plagued by rubbish and open sewage, some of which have been taken over by criminal gangs.

There's guns, there's drugs, there's prostitutes, there's everything here, said Nelson Khetani, resident of a building known as MBV1, located in Joubert Park.

Neglect and a lack of maintenance have left vandalized communal kitchens stripped of their fittings, while overflowing human waste covers parts of what used to be the laundry area.

Mr. Khetani told BBC Africa Eye that rooms in MBV1 had been hijacked – a phenomenon where spaces or entire residential units are taken over and controlled by criminals to collect rent for themselves and, in some circumstances, provide a base for illegal activities.

The BBC has located and confirmed that there are 102 derelict or abandoned buildings in the inner city, but some media reports cite much higher figures. Many of these buildings are unfit for human habitation.

The state of the city was on the mind of President Cyril Ramaphosa when he spoke about the G20 summit at the city council in March, stating, It is a painful sight to go through the center of the city… you have a number of abandoned buildings, buildings that have been hijacked, that are not paying your rates and taxes.

Johannesburg Mayor Dada Morero insisted at the time that the city was ready to host the G20. However, the clean-up campaign initiated last month faces significant obstacles amidst widespread lawlessness and illegal activities.

A tragic fire in one of these derelict buildings that killed 76 people two years ago was supposed to spur action, yet not much has changed.

In another grim report, residents at a building named Vannin Court spoke of reliance on makeshift gas stoves for cooking and the severe lack of basic utilities, with sewer issues persisting in the vicinity.

The conditions within these buildings resonate with a reality steeped in a history of rapid urban migration post-apartheid. Many residents moved to inner city locations for proximity to jobs, but the influx coupled with neglect has led to dreadful living conditions.

Criminal hijacking of properties continues to be a rampant issue in Johannesburg, with insiders revealing how buildings have become hubs for illicit drug activities.

Despite rhetoric from city officials about rehabilitating these spaces for dignified living conditions, the situation remains dire for the residents of these hijacked developments.

Johannesburg faces a tough challenge of balancing the urgent need for urban renewal against the legal and financial complexities of evictions and redevelopment, leaving many residents questioning when a solution will finally come.