Spatial Dynamics of Urban Expansion and Planning Disparities in the Islamabad–Rawalpindi Conurbation
This study utilizes remote sensing and spatial analysis to reveal that the Islamabad–Rawalpindi conurbation experienced a 101% increase in built-up land between 2011 and 2024, characterized by irregular growth phases, significant forest loss, and a stark disparity where the unplanned Rawalpindi District expanded nearly twice as fast as the planned capital, underscoring the urgent need for green-belt enforcement and conurbation-scale governance.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Cities are not just collections of buildings; they are living landscapes that constantly reshape the ground beneath them. When a city grows, it does not simply add more houses; it transforms the very nature of the land, turning fields, forests, and open soil into paved surfaces that change how water flows, how heat is stored, and how wildlife survives. Scientists who study these changes look for patterns in the chaos, asking not just how fast a city is growing, but how it is growing. Is it filling in empty spaces between existing buildings, creating a tight, efficient community? Or is it spreading out in a scattered, low-density way that consumes vast amounts of land? This distinction matters deeply for the future of urban life, as the shape of a city determines its environmental cost and its ability to function sustainably. In South Asia, where some of the world's fastest-growing urban regions are located, understanding these patterns is critical for planners trying to balance development with the preservation of natural resources.
In a recent study, researchers turned their attention to the twin cities of Islamabad and Rawalpindi in Pakistan, a massive urban region that covers more than 6,000 square kilometers. This area offers a unique opportunity to observe two different ways of city-building side by side. Islamabad is a planned capital, designed with a strict grid, wide boulevards, and designated green spaces, growing under formal government rules. Just next to it lies Rawalpindi, an older city that has grown organically over centuries with far less oversight, expanding into the surrounding countryside in a more scattered fashion. By treating these two neighboring areas as a natural experiment, the researchers could compare how a regulated city grows versus an unregulated one, using satellite images to track the changes over a thirteen-year period from 2011 to 2024.
The team used advanced computer software to analyze satellite photographs taken during the dry seasons of 2011, 2016, 2021, and 2024. They taught the computer to recognize six different types of land cover, such as water, dense forest, crops, bare soil, and the built-up areas of cities. The computer's classification was highly accurate, correctly identifying the type of land in nearly 80 percent of cases. Once the maps were created, the researchers measured exactly how much the city had grown. The results were striking: the total area covered by buildings and roads in the entire region doubled over the thirteen years. The built-up land expanded from roughly 384 square kilometers to 772 square kilometers, an increase of more than 100 percent. This new urban land did not appear out of nowhere; it was carved primarily from natural vegetation, bare soil, and the forested slopes of the Margalla Hills, which saw a significant decline in coverage.
However, this growth did not happen at a steady pace. The researchers found that the expansion occurred in three distinct waves. The first wave, between 2011 and 2016, was a rapid surge where the city spread out quickly. This was followed by a noticeable slowdown between 2016 and 2021, a period that coincided with global economic shifts and the pandemic, before a second, even more intense burst of growth occurred between 2021 and 2024. The most recent years saw the fastest rate of expansion in the entire record, suggesting that pressure on the remaining open land is rising sharply.
The shape of this growth told an even more important story. The researchers measured how scattered or concentrated the new buildings were. They found that the overall pattern of the city was consistently dispersed, meaning the urban area was spreading out rather than staying tight and compact. The most scattered phase occurred during that first rapid surge between 2011 and 2016, when new development appeared in a fragmented, leapfrog pattern across the landscape. After a period of consolidation where the city filled in some of those gaps, the growth became scattered again in the final years. Crucially, the direction of this expansion was not uniform. The city grew heavily toward the south and southeast, following major roads and corridors into the plains, while the northern edge remained blocked by the forested hills.
The most revealing finding came from comparing the two cities directly. The unplanned district of Rawalpindi grew nearly twice as fast as the planned capital of Islamabad. While the planned city added new buildings at a steady, controlled rate, the unplanned district absorbed more than three-quarters of all the new urban land in the entire region. In the planned area, new development tended to fill in existing gaps, making the city more compact. In the unplanned area, the city grew by creating many new, separate patches of development, leading to a fragmented landscape. This contrast highlights a key reality: strict planning within a city center does not necessarily stop sprawl at the edges. Instead, development often shifts to the less regulated areas just beyond the city limits, consuming land and forests in the process.
The study concludes that the future of this region depends on managing growth across the entire urban area, not just within the planned boundaries. The researchers suggest that protecting the forested hills on the northern edge is essential, as that is where the most significant loss of natural cover is occurring. They also recommend focusing new development along the southern transport corridors to make better use of existing infrastructure, rather than letting the city spread randomly into open fields. By using freely available satellite data and open-source tools, the researchers have provided a clear, measurable picture of how urban expansion works in this part of the world, offering a blueprint for other cities facing similar challenges. The evidence shows that without coordinated management across the entire region, the natural landscape will continue to be sacrificed to the relentless, scattered spread of the city.
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