Understanding Delhi’s Vegetation Dynamics: A GIS and Climate Perspective

Author: Deepak Kumar Raj (Product Specialist, R&D)

Introduction: The Battle Between Concrete and Greenery

Delhi, a city of over 30 million people, is a fascinating mix of rapid urbanization and resilient green spaces. From the dense forests of the Ridge to the sprawling parks in South Delhi, vegetation plays a crucial role in cooling the city, improving air quality, and supporting biodiversity. But how is Delhi’s greenery responding to climate change, and what tools do we have to monitor it?

A recent study titled “Soft Computing Techniques for Predicting Vegetation Dynamics in Delhi” sheds light on these questions by analyzing satellite data, climate variables, and advanced machine learning techniques. In this blog, we’ll explore how geographic information systems (GIS) and climate science help us understand Delhi’s vegetation trends—without diving too deep into technical jargon.

Whether you’re a curious resident, an environmental enthusiast, or a policymaker, this blog will give you a clear picture of Delhi’s green cover and what influences it.

Why Vegetation Matters in a Megacity Like Delhi

Before we dive into the science, let’s understand why vegetation is so crucial for Delhi:

1. Fights Urban Heat Islands – Concrete absorbs heat, making cities hotter. Trees and parks help cool the air.
2. Improves Air Quality – More greenery means less pollution, a critical need for Delhi’s notorious smog.
3. Supports Water Management – Healthy vegetation reduces flooding by absorbing rainwater.
4. Boosts Mental Well-being – Green spaces provide relief from the stress of city life.

But how do we measure vegetation health? That’s where satellite technology and GIS come in.

Satellite Eyes on Delhi: How Scientists Track Vegetation

1. The Magic of NDVI – Measuring Greenness from Space

Scientists use a tool called the Normalized Difference Vegetation Index (NDVI), which calculates how green an area is based on satellite images.

• How It Works:
  • Healthy plants reflect more near-infrared light (invisible to our eyes).
  • Dry or sparse vegetation reflects more red light.
  • NDVI combines these two to give a vegetation health score between -1 (no vegetation) and +1 (dense forest).
• Delhi’s NDVI Trends (2002-2022):
  • 2002: Average NDVI = 0.28
  • 2022: Average NDVI = 0.34 (a noticeable improvement!)
  • Best-Performing Areas: North West and South Delhi (thanks to the Ridge and large parks).

2. Land Surface Temperature (LST) – Why Some Parts of Delhi Feel Hotter

Satellites also measure Land Surface Temperature (LST), which tells us how hot the ground is—not the air temperature we feel.

• Key Findings:
  • Concrete-heavy areas (Central, East Delhi) have higher LST.
  • Green zones (like the Ridge) are cooler by several degrees.
  • Surprisingly, LST had almost no direct impact on NDVI in Delhi, unlike other cities.

3. Rainfall & Evapotranspiration – The Water Connection

Plants need water, and Delhi’s vegetation relies heavily on:

• Rainfall (Precipitation):
  • More rain = better vegetation growth.
  • But Delhi’s rainfall is unpredictable, leading to fluctuations in greenery.
• Evapotranspiration (ETo):
  • This measures how much water plants release into the air.
  • Strongest correlation with NDVI (0.78)—meaning healthier vegetation leads to higher ETo.

Mapping Delhi’s Green Zones: A GIS Perspective

1. The Power of GIS in Urban Planning

Geographic Information Systems (GIS) help visualize and analyze spatial data. In this study by (Raj D K & T Gopikrishnan), GIS was used to:

✔ Create annual vegetation maps (2002, 2012, 2022).
✔ Compare different districts (e.g., North Delhi vs. South Delhi).
✔ Identify urban heat islands (areas with high LST and low greenery).

2. Key Observations from the Maps

• North West & South West Delhi – Highest greenery due to forests and planned parks.
• Central & East Delhi – Lowest greenery, highest temperatures (more concrete, less trees).
• Yamuna Floodplains – Surprisingly, not as green as expected, possibly due to pollution and encroachment.

3. Why Some Areas Are Greener Than Others

• Policy Impact: Areas like Lutyens’ Delhi (New Delhi) have strict tree protection laws.
• Urban Sprawl: Unplanned growth in outer districts (like North East Delhi) reduces green cover.
• Water Availability: Places near the Yamuna or with better irrigation (like parks) sustain more vegetation.

Climate Change & Delhi’s Future Greenery

1. Rising Temperatures – A Silent Threat

While LST doesn’t directly reduce NDVI in Delhi, long-term heat waves can:

• Increase water evaporation, stressing plants.
• Make it harder for new trees to survive.

2. Erratic Rainfall – Feast or Famine for Plants

• Some years, Delhi gets excessive monsoon rains, boosting greenery.
• Other years, drought-like conditions lead to dried-up parks and grasslands.

3. Can Delhi Increase Its Green Cover?

The study suggests:
 More Urban Forests – Like the Ridge, which cools surrounding areas.
Rooftop & Vertical Gardens – To compensate for lost ground space.
 Better Water Management – Ensuring parks and trees get enough water in dry months.

What Can Citizens Do?

1. Plant Native Trees – Species like Neem, Peepal, and Bargad survive Delhi’s climate best.
2. Support Urban Greening Projects – Join local initiatives like “Delhi Tree Challenge.”
3. Reduce Concrete Surfaces – Opt for permeable pavements in homes to allow water absorption.

Final Thoughts: A Greener Delhi Is Possible

Delhi’s vegetation is a lifeline—fighting pollution, cooling the city, and providing much-needed natural beauty. Thanks to satellite technology and GIS, we now have a clearer picture of how climate and urbanization affect our green spaces.

While the city has made progress (NDVI increased from 0.28 to 0.34 in 20 years), there’s still a long way to go. With smarter urban planning, community efforts, and climate-resilient policies, Delhi can become a model for sustainable megacities.

What’s your take? Should Delhi prioritize more parks, urban forests, or better water management? Share your thoughts in the comments!

Want to explore the data yourself? Check out:

• Google Earth Engine for satellite imagery.
• CHRS Rainfall Data for precipitation trends.

Let’s work together to keep Delhi green!