Saving the city from the ground up

Every year on December 5, the world pauses to honour one of the most essential yet overlooked foundations of human life: soil. World Soil Day, instituted by the FAO of the United Nations, is not merely an environmental observance; it is a global reminder that the thin living layer beneath our feet quietly sustains our food, ecosystems, economies, and wellbeing.

In 2025, the theme “Healthy Soils for Healthy Cities” invites the world to shift its attention from rural farms to the ground beneath urban landscapes. With over 56% of the global population now living in cities, the health of urban soils has become critical to addressing many of the challenges modern cities face: food insecurity, pollution, extreme heat, flooding, water scarcity, and declining green spaces. This year’s theme highlights that the resilience of India’s cities depends--quite literally--on the soil they stand upon.

When people think of soil, they imagine farmlands, forests, or countryside fields. Yet every city—beneath parks, tree-lined streets, medians, playgrounds, and backyard gardens—is supported by soil that performs extraordinary ecological functions.

Healthy urban soils play a vital role in creating liveable cities. They help regulate climate by reducing the urban heat island effect, where city temperatures can rise 3–8°C above surrounding areas. Vegetated soils act as natural coolants, supporting green belts, parks, and community gardens that function as urban “air conditioners”. They also prevent flooding, an increasing threat as climate change intensifies rainfall, by absorbing stormwater, filtering it, and replenishing groundwater, unlike concrete surfaces that cause waterlogging.

Beneath the surface, healthy soil hosts a vast web of life—bacteria, fungi, insects, and earthworms—that supports pollination, decomposition, and plant growth. This living soil is also the foundation of urban agriculture, from rooftop beds to backyard gardens, helping families grow fresh food and reducing dependence on long supply chains. Equally important, soil-rich green spaces improve mental and physical wellbeing, providing “Vitamin N” through gardening and nature contact, which reduces stress and boosts community health.

Despite its enormous value, urban soil is among the most degraded natural resources. The FAO warns that nearly one-third of the world’s soils are degraded, and city soils face the harshest pressures:

Contamination from industrial waste, construction debris, chemicals, petroleum residues, and heavy metals

Compaction from heavy machinery, reducing infiltration and killing soil organisms

Loss of organic matter when topsoil is removed during construction

Paving and soil sealing with concrete and asphalt, which suffocates soil life and disrupts the water cycle

These pressures weaken plant growth, threaten food safety in community gardens, reduce groundwater recharge, and harm the ecosystems that make cities liveable.

World Soil Day 2025 therefore issues an urgent call: cities cannot thrive without healthy soil,
and soil cannot remain healthy without informed, responsible communities.

This year’s theme is a framework for action that encourages governments, planners, schools, and residents to become custodians of the soil beneath their feet.

Urban soil restoration and protection: Cities must rehabilitate degraded soils using compost, organic amendments, mulching, and microbial inoculation. Protecting existing soils from further sealing is equally essential.

Expanding green infrastructure: Replacing paved surfaces with soil-based solutions—parks, bioswales, rain gardens, green corridors, and tree belts—helps reduce flooding, cool cities, and support biodiversity. Soil should be recognised as a vital part of urban infrastructure.

Championing urban agriculture: Backyard gardens, community farms, and rooftop plots are powerful tools for improving soil health and strengthening local food systems. Even small steps—growing herbs in balcony pots or maintaining a tiny vegetable patch—contribute to urban resilience.

Practicing responsible gardening: Residents can support soil health by adopting eco-friendly methods: reducing chemical fertilisers, avoiding pesticide misuse, planting native species, minimising tilling, and protecting topsoil through mulching.

Urban progress must not be measured only in buildings and roads but also in how well we protect the natural systems that allow cities to function.

(The writer is an ex-Emeritus Soil Scientist, ICAR-IIHR,
Bengaluru)