In a sprawling metropolis like Delhi, where concrete often replaces canopies and the monsoon brings the dual anxiety of parched ground and flooded streets, a quiet ecological miracle is at work.
A new study by researchers at the University of Delhi has revealed that the Aravalli Biodiversity Park – a 692 acre sanctuary on the city’s southern ridge is doing the heavy lifting for Delhi’s environment. Most notably, the park helps the capital retain nearly three million litres of rainwater every single year.
Healing the Scars of the Past
To truly appreciate what the park accomplishes today, you have to look at what it used to be. Not long ago, this land was a heavily degraded mining site, hollowed out for morrum (the reddish gravel used in construction). Nearly 80% of the landscape was a scarred wasteland of abandoned pits, waste mounds, and barren earth. What little grew there was dominated by stubborn, invasive species like vilayati kikar and lantana.
Today, thanks to years of dedicated restoration work, those deep mining scars have been transformed into a thriving mosaic of native forests, grasslands, and wetlands. The park is now home to around 700 plant species across 20 distinct ecological communities, providing a sanctuary for a vast array of urban wildlife.
A Natural Shield Against Monsoon Chaos
Delhi’s climate is notorious for its sharp contrasts, receiving the vast majority of its annual 774.4 mm of rainfall in a sudden, intense burst between July and September. In a fast-urbanizing city dominated by paved surfaces, this water usually translates into severe street flooding and waterlogging.
The Aravalli Biodiversity Park acts as a giant natural sponge. Sitting right on a crucial groundwater aquifer recharge zone, its uneven terrain originally shaped by mining now works to slow down rushing rainwater. Instead of turning into destructive surface runoff, the water is gently paused by the forest floor, allowing it to seep deep into the earth and replenish Delhi’s dwindling underground reserves.
Delhi’s Giant Green Lung
The benefits don’t stop at water management. The University of Delhi study which analyzed the forest using the advanced i-Tree Eco model highlights that the park’s estimated 2.02 lakh trees are pulling massive shifts in purifying the air and fighting climate change.
- Breathing Room: The structurally diverse forest is incredibly effective at trapping airborne pollutants. Researchers estimate the park cleans 126.89 tonnes of air pollutants from the atmosphere every year an environmental service valued at nearly ₹1.89 crore.
- The Carbon Vault: The park has grown into a powerful carbon sink. Its trees currently store about 8,360 tonnes of carbon (valued at ₹11.34 crore) and absorb an additional 1,236 tonnes of new carbon every year as they grow.
The Power of Native Diversity
The secret to the park’s success lies in the deliberate choice of native trees. Led by dominant species like palash, Indian elm, white-barked acacia, and kadamb, the forest’s high biodiversity creates a resilient ecosystem. The study noted that trees with thicker trunks, greater height, and wider canopies are the real champions, capturing the highest amounts of carbon and particulate matter.
More than just a beautiful escape from the city’s chaos, the Aravalli Biodiversity Park stands as a living proof of concept. It shows that with patience and ecological wisdom, human beings can heal even the most damaged landscapes turning a barren wasteland into an indispensable shield against urban flooding and climate stress.
This comprehensive study, titled “Structure, ecosystem services and economic evaluation of native tree diversity: a case study of the restored Aravalli Biodiversity Park, Delhi, India”, was jointly conducted by researchers from the Centre for Environmental Management of Degraded Ecosystems, the Biodiversity Parks Programme, the Department of Finance and Business Economics, and Satyawati College.