Authors: Dr.  Suresh Kumar and Dr. R. P Singh, IIRS

Urbanization is reshaping the earth planet, with nearly 70 percent of the global population expected to live in cities by 2050. India’s urban population was 36.36% in 2023 and expected to reach 50% by 2050. As cities continue to grow, they face increasing environmental challenges such as solid waste, industrial effluents, flooding and vehicle-related emissions. These impacts in general remain unnoticed, yet they adversely affect densely populated urban area. Additionally, many cities are experiencing the Urban Heat Island (UHI) effect, which contributes to rising temperatures and global warming.

Keeping in view of these alarming challenges of cities, December 5, 2025, is being observed as the United Nations World Soil Day (WSD) with the theme “Healthy Soils for Healthy Cities.” This theme emphasizes the critical role of soils in sustaining healthy and resilient urban ecosystems. Healthy urban soils play a vital role in water filtration, carbon storage, temperature regulation, ground water recharge and supporting biodiversity and urban food production.

High-resolution remote sensing satellite data (IRS Cartosat series and Resourcesat series LISS-IV) are widely used to characterize the urban environment, including detailed land use/land cover (LULC) types, landscape features, soil types, geomorphology, building infrastructure, and other information necessary for sustainable urban development planning. Digital Terrain Models (DTMs) generated from stereo satellite data and airborne sensors are used to derive terrain variables such as micro-relief, runoff flow direction, flow accumulation, and the Topographic Wetness Index (TWI). These terrain variables, along with detailed soil information—such as soil texture, soil depth, and soil drainage conditions—help identify and characterize potential waterlogged and flood-prone areas in and around cities. This critical information supports the identification of suitable sites for various urban land uses; guides planned urban expansion, and informs appropriate measures to mitigate environmental challenges, thereby promoting healthier living conditions in urban areas.

Soils act as natural filters by adsorbing or immobilizing toxic heavy metal and organic contaminants, thereby preventing their transfer into water and food systems and minimizing their impact on urban environments. Soil macro-organisms further enhance water infiltration and contribute to the retention and removal of pathogens, and other pollutants within urban area. However, urbanization through the expansion of buildings, roads, and other infrastructure often results in soil sealing and compaction, reducing water infiltration resulting poor groundwater recharge. Healthy soils function as a “sponge”, absorbing water, improving groundwater levels and their quality as well as supporting vegetation that helps in maintaining urban greenery.

Urbanization negatively affects soil functions by degrading natural habitats, fragmenting landscapes, and altering ecosystem dynamics. These disturbances increasing the risks of flooding and waterlogging, which cause risk of various human diseases. Urbanization adversely affects soil biodiversity, can be mitigated through provision of green roofs and walls, indoor green habitats, diversified or restored urban parks, urban forest and urban agriculture. These will helps in improving overall quality of urban environment, with positive implications for public health and their well-being. Studies have shown that children who grown up on farms, compared to those in urban environments, tend to have stronger immune systems due to their exposure to a wider diversity of environmental microorganisms. Even indoor plant–soil systems can help to regulate beneficial airborne microbial population that support human health.

Therefore, this year’s World Soil Day theme serves as an important reminder of the need to maintain healthy soils and promote urban green spaces. Enhancing vegetation in urban areas, helps keep cities cooler, reduces flooding, improves air quality, and can even contribute to local food production. It will foster healthier urban living and strengthen essential ecosystem services, supporting the goal of creating sustainable and resilient cities for the future.

References

• Roberts, M, Deuskar, C, Jones, N and Park, J. (2023). Unlivable: What the Urban Heat Island Effect Means for East Asia’s Cities. Washington DC: World Bank.
• Sun, X., Liddicoat, C., Tiunov, A. et al. (2023). Harnessing soil biodiversity to promote human health in cities. npj Urban Sustain 3, 5. https://doi.org/10.1038/s42949-023-00086-0
• UNICEF. (2018). Advantage or Paradox? The challenge for children and young people of growing up urban. Retrieved from UNICEF at https://data.unicef.org/resources/urban-paradox-report/
• https://www.fao.org/world-soil-day/en/