Q(GS1, 2022): "Urban Heat Islands are a Consequence of Unplanned Urbanization." Discuss.

  Q(GS1, 2022): "Urban Heat Islands are a Consequence of Unplanned Urbanization." Discuss.

Introduction

Urban Heat Islands (UHIs) refer to significantly higher temperatures in city centres compared to surrounding rural areas, primarily due to human activities and poor urban planning. The World Bank’s recent report highlights that Indian cities are 3-4°C hotter than their outskirts, confirming the severe impact of unplanned urbanization on UHIs.

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What are Urban Heat Islands?

An Urban Heat Island (UHI) is a localized warming effect caused by:

• Replacement of natural vegetation with concrete and asphalt.
• High density of buildings, vehicles, and industries emitting waste heat.
• Poor ventilation due to clustered high-rise structures.

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How Does Unplanned Urbanization Cause UHIs?

1. Loss of Green Cover

• Unplanned expansion leads to deforestation and shrinking parks.
• Example: Delhi has lost 25% of its green cover in the last two decades, worsening heatwaves.

2. Proliferation of Concrete & Asphalt

• Dark surfaces (roads, rooftops) absorb and retain heat.
• Example: Chennai’s average temperature rose by 2°C due to unchecked construction.

3. Heat Trapping Due to High-Rise Buildings

• Canyon effect: Tall buildings trap heat and reduce wind flow.
• Example: Mumbai’s Nariman Point is 5°C hotter than suburbs due to dense skyscrapers.

4. Waste Heat from Vehicles & Industries

• Unregulated industrial zones and traffic congestion increase ambient heat.
• Example: Bangalore’s Whitefield IT hub faces higher temperatures due to heavy AC usage.

5. Reduced Water Bodies

• Lakes and wetlands act as natural coolants, but unplanned construction has destroyed them.
• Example: Hyderabad lost 3,245 hectares of lakes in 30 years, intensifying UHI effects.

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Consequences of Urban Heat Islands

1.    Health Risks: Increased heat strokes, dehydration, and cardiovascular diseases.

2.    Higher Energy Demand: Excessive AC use leads to power shortages.

3.    Reduced Air Quality: Trapped pollutants worsen respiratory illnesses.

4.    Economic Losses: Heat stress reduces worker productivity (up to 15% GDP loss by 2030, as per ILO).

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Solutions to Mitigate UHIs

Measure	Example
Green Roofs & Cool Pavements	Delhi’s cool roof policy for slums
Urban Afforestation	Mumbai’s Aarey Forest revival
Waterbody Restoration	Chennai’s Rainwater Harvesting
Better Zoning Laws	Mixed land-use policies in Pune
Public Transport Expansion	Metro networks in Bangalore

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Case Study: Delhi’s Heat Action Plan

• Cool Roofs: Reflective paint on 5,000+ low-income houses.
• Tree Transplantation Policy: Mandates replanting for infrastructure projects.
• Early Warning Systems: IMD alerts for heatwaves.

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Conclusion

Unplanned urbanization directly exacerbates Urban Heat Islands by replacing natural cooling systems with heat-absorbing structures. However, sustainable urban planning, green infrastructure, and policy reforms can reverse this trend. For India to achieve its Smart Cities Mission, integrating climate resilience into urban development is non-negotiable.

"Cities must grow vertically with green lungs, not just concrete jungles."

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