Context

• Urban India is becoming a heat-trap. It is important to strengthen resilience through effective building materials and zone-specific master plans.

Urban heat island effect

• The Urban Heat Island (UHI) effect refers to localized areas within cities or metropolitan areas that experience significantly higher temperatures when compared to surrounding regions. 
• Urban heat island is basically induced due to trapped heat between establishments made up of concrete.
• The temperature variation can range between 3 to 5 degrees Celsius.

Factors contributing to a rise in UHI effect 

• Extensive infrastructure development, characterized by concrete, asphalt, and buildings with heat-absorbing materials, leads to increased heat retention and accumulation in urban areas.
• Manufacturing processes, factories, and commercial establishments in cities contribute to localized heating.
• High levels of air pollution in urban areas trap heat near the surface, exacerbating the UHI effect.
• High population density in urban areas results in increased energy use, and transportation, thereby adding to the thermal load of cities.
• High-density urban development can restrict air circulation, reducing natural ventilation and increasing heat retention.

Mitigating UHI effect

• Aspect Ratio: The ratio of building height and street width plays a role in how much heat will be trapped by the roads, pavements and building surfaces. Higher the Aspect ratio, lower will be the land surface temperature.
• Green infrastructure: Greens play a crucial role in enhancing microclimate of an urban area. They regulate temperature and relative humidity, absorb and decompose pollutants, improve the overall air quality.
• Energy-Efficient Buildings:Encouraging the use of energy-efficient building designs, such as those with better insulation and shading, reduces the urban heat island effect by minimizing the overall energy consumption for heating and cooling.
• Promoting Sustainable Transportation: Encouraging walking, cycling, and the use of public transportation reduces vehicular emissions and, consequently, the heat island effect caused by exhaust gases and heat from vehicles.
• Permeable Pavements: Utilizing permeable or porous pavements allows water to infiltrate and aid in stormwater management.
• Heat-Resistant Pavements: Developing pavements with materials that have a higher resistance to heat absorption can help reduce surface temperatures in urban areas.

Conclusion

• Addressing the UHI effect requires comprehensive policies, community involvement, and concerted efforts at the national, state, and local levels.
• Implementation of effective urban planning and sustainable development practices can help mitigate the adverse effects of UHI and improve overall urban livability.