Unequal access to modern infrastructure is a feature of growing cities, according to a study published this week in the Proceedings of the National Academy of Sciences by researchers from Yale University School of the Environment and Oak Ridge National Laboratory.

Understanding this infrastructure inequity is a key step toward sustainable development. That’s because systems like electrical networks and water lines are so durable, they can lock in unequal access for many decades.

Researchers Bhartendu Pandey, Christa Brelsford and Karen Seto developed a novel approach to evaluate infrastructure inequality in two emerging economies of the Global South: India and South Africa. They analyzed population information from national census results, as well as nighttime satellite imagery where highly lit areas indicated the presence of infrastructure. These methods were used to measure inequality in four types of infrastructure: electricity, clean water, sanitation and housing.

Brelsford, who at the time was a Liane B. Russell Distinguished Fellow at ORNL, helped lead author Pandey develop the experimental design and analyze the results for his doctoral research at Yale. His idea for the study grew out of a mathematical framework Brelsford previously developed, which showed increased availability of infrastructure didn’t necessarily reduce inequality in its access.

“Over the next century, we need to build as much urban infrastructure as we have built in the history of humanity,” said Brelsford, a research scientist in ORNL’s Geospatial Science and Human Security Division. “The choices we make now will have profound effects on the lived experience of everybody on the planet, so we should get it right.”

Focusing on infrastructure inequality can help urban planners understand the implications, persistence and predictability of inequality in growing cities, as well as its unintended consequences and how to mitigate it.

The study’s findings demonstrated greater infrastructure inequalities in South Africa than in India and greater inequality in urban than rural areas. (These results mirrored differences in economic inequality.) The imbalance increased at regional scales, a finding that challenges common approaches that focus on just one or two cities to reduce urban disparities.  

Uneven access to urban infrastructure increased along with population and infrastructure development, although the correlation was higher in India than in South Africa. (This was not unexpected, Pandey said, because South Africa’s long-standing system of apartheid created built-in bias when infrastructure was first installed there.)

Other results were more surprising. Researchers did not find a correlation between infrastructure inequality and race, religion or similar socio-cultural factors. And although economic and infrastructure inequality sometimes overlap, they are not aligned overall, Brelsford said. “Our intuition is that they will behave in sort of the same ways, and the reality is that they don’t,” she said. This is partly because infrastructure like water and electricity distribution is inherently connected.

Pandey, who is now a post-doctoral researcher at Princeton University’s Urban Nexus Lab, grew up in a part of Delhi with limited infrastructure. “One thing that struck me is that inequality is a systemic problem deeply rooted in the urbanization process,” he said. “That requires us to be thinking about inequality in the urban context beyond income and wealth.”

The study noted that high levels of inequality can undermine economic productivity, entrench environmental injustice and magnify the impacts of economic, social and environmental shocks.

Two measurements, 10 cups of water

Although the census and satellite imagery data were analyzed separately, the findings were similar, the authors said.

The satellite data provided information about where infrastructure was available, while the census data helped explain how access is “provisioned” — that is, whether it is divided equally among those who have access.

Pandey compared it to 10 cups ready to be filled with water. The cups are available, but inequality can arise in deciding how to fill them. “More than likely, you’re going to fill them up one by one,” he said. “And when you are doing so, it’s the most unequal way to fill the cups. Because at one point, you’ll have one cup full, and all the others empty.” This is how the process of urbanization often plays out.

But expanding infrastructure in growing cities provides an opportunity to reconsider how to “fill the cups” to equitably distribute even a small amount of resources. “Why aren’t we using two hands? Why can’t I have more friends help fill the cups? It’s a matter of being cognizant about the fact that we ought to be reducing inequalities,” Pandey said. “Particularly in countries that are rapidly urbanizing, such as India, this is very important — because how we urbanize now is going to shape how inequalities look far into the future.”

It also affects progress toward sustainable development, as 72% of the targets associated with United Nations’ sustainable development goals are related to infrastructure.

Pandey said the study results suggest several avenues for further inquiry. For example, he noted that the nighttime satellite imagery could be analyzed to understand infrastructure availability in every country worldwide. He also sees a need for further research about how inequality manifests in specific types of infrastructure, such as internet access.

Pandey is already investigating inequalities among assets owned by households in India, and he’s beginning an effort to develop a computational framework for understanding changes in inequality using satellite data from multiple sources.

Brelsford said their infrastructure study contributes to developing an intellectual framework for thinking about diversity within and among cities.

“We’re used to thinking about a city as just a bundle of people and stuff,” she said. Instead, cities should be regarded as heterogenous spaces where resources are distributed unevenly. “That has really profound impacts on outcomes for real people and for how we solve the global-scale problems we face, from health to climate change,” Brelsford said.

UT-Battelle manages ORNL for the Department of Energy’s Office of Science, the single largest supporter of basic research in the physical sciences in the United States. The Office of Science is working to address some of the most pressing challenges of our time. For more information, please visit energy.gov/science. — S. Heather Duncan