[Answered] “The urban heat island effect is significantly exacerbating summer temperatures in many Indian cities, posing serious challenges to public health, energy consumption, and overall urban sustainability.” Discuss.

Introduction

The Urban Heat Island (UHI) effect refers to the phenomenon where urban areas record significantly higher temperatures than their surrounding rural counterparts due to factors like concretization, vehicular emissions, and reduced vegetation. This phenomenon is intensifying in Indian cities such as Bengaluru, Delhi, and Ahmedabad, aggravating summer heatwaves and undermining urban resilience.

Exacerbation of Summer Temperatures: The Case of Bengaluru

Bengaluru, once known as India’s “Garden City”, has witnessed an alarming rise in UHI-induced temperature spikes:

• Tree cover has declined from 2% in 1973 to just 6.02% in 2025 (IISc data).
• Average temperatures have surged from 19°C (1990s) to 36–38°C (2020s).
• White-topped roads, glass-façade buildings, and unplanned infrastructure projects like Metro Phase 3 (which threatens over 11,000 trees) are key contributors.

These urban interventions have turned the city into a concrete heat trap, with certain localities reporting 3–5°C higher temperatures than surrounding areas.

Challenges Posed by UHI

1. Public Health Crisis: Elevated temperatures increase risks of heat strokes, respiratory distress, and cardiovascular issues, particularly among children and the elderly. A Curtin University study links UHI intensity to heightened urban health vulnerabilities.
2. Energy Consumption: UHI escalates cooling demand, particularly in buildings with glass façades that consume 10 times more electricity than regular buildings. This not only strains the grid but also exacerbates greenhouse gas emissions, contradicting India’s climate goals.
3. Water Scarcity: Concretization impedes groundwater recharge. Contrastingly, rejuvenation of lakes like Sarakki Lake has improved local microclimates and groundwater levels.
4. Urban Unsustainability: Green space per capita falls short of WHO’s 9 sq. m recommendation, reducing liveability and environmental equity in urban India.

Way Forward

1. Strengthen Heat Action Plans: Karnataka’s Heat Wave Action Plan recommends vertical gardens, water fountains, and urban greening.
2. Enforce Green Building Norms: Promote ECBC-compliant designs and phase out energy-intensive structures.
3. Nature-Based Solutions: Rejuvenate lakes, plant urban forests, and protect tree cover.
4. Citizen Engagement: Involve civil society in tree censuses and afforestation efforts.

Conclusion

The UHI effect reflects the ecological cost of rapid, unplanned urbanization. Mitigating its impact is essential to ensure that Indian cities remain habitable, sustainable, and climate-resilient in the face of escalating summer extremes.