A new study warns that rapid urban growth could leave millions of people without access to clean water and sanitation by 2050. Experts say how cities expand and where new buildings are constructed will directly affect the health and daily lives of hundreds of millions of residents.

Researchers from the Complexity Science Hub in Vienna and the World Bank studied more than 100 cities across Africa, Asia, and Latin America. They analyzed data from 183 million buildings and 125,000 households to understand how urban expansion could impact water and sanitation services.

The study outlined three models for city growth by 2050: compact development, maintaining current patterns, and horizontal expansion into new areas. The report found that horizontal growth could cut clean piped water access for 220 million people and sewage services for 190 million. Compact growth would reduce these risks and improve efficiency, while sprawling cities have water bills roughly 75 percent higher than compact cities. People living on city outskirts also have 40 percent less access to basic services compared to those near city centers.

Lead researcher Rafael Prieto-Curiel said proper urban planning can reduce water scarcity. Compact, walkable neighborhoods with the right density can provide essential services to all residents without new infrastructure, while also being environmentally sustainable.

The study also highlights that by 2050, urban populations in Africa could triple, and in Asia could rise by nearly half. African cities are already more spread out, with only 12 percent of residents living near the center, compared to 23 percent in Asia.

With inputs from NDTV