Note4Students

From UPSC perspective, the following things are important :

Prelims level: Urban Form

Mains level: Urban Heating

urban form

Central Idea

A study conducted by the Centre for Science and Environment (CSE) in 2022 examines the relationship between diverse urban forms and their reactions to heat, offering insights that could guide India’s urban centers in combatting heat-related challenges.

Distinct Urban Forms and Heat Resilience

Crucial Consideration: Urban form encompasses a city’s unique blend of natural and built components, shaping its activities and infrastructure.
Diverse Parameters: Urban form’s defining elements include urban morphology, aspect ratio, sky view factor (SVF), blue/green infrastructure (B/GI), floor space index (FSI), and street orientation.
Localized Study: CSE’s ongoing study focuses on 10 cities, such as Pune, Delhi, Kolkata, Bengaluru, and Jaipur, each revealing trends that could inform heat mitigation strategies.

Unveiling Key Parameters and Findings

Urban Morphology: Varied urban morphologies, from open highrise to compact midrise, demonstrate lower land surface temperatures (LST) among heat pockets. Lowrise areas exhibit higher LST due to sparse vegetation and heat-trapping roofing materials, suggesting the potential for improvement.
Aspect Ratio: The ratio of building height to street width impacts heat retention. Higher aspect ratios correlate with lower LST, indicating the significance of narrower streets for reduced heat gain.
Sky View Factor: The visibility of sky between buildings influences heat dissipation. Elevated sky view factors increase LST by up to 10°C, highlighting the role of factors like road intersections and open parking lots.
Blue/Green Infrastructure: Vegetation significantly impacts microclimates. Effective vegetation cover (EVC), with a focus on trees, grass, and shrubs, can reduce LST by 2-4°C, demonstrating the need to prioritize tree-heavy greens.

Policy Implications for Enhanced Heat Resilience

FSI and Urban Cooling: Higher floor space index (FSI) inversely correlates with LST, suggesting that denser urban configurations can alleviate heat.
Street Orientation: The orientation of streets affects sun exposure and wind, leading to differences in thermal comfort. North-south streets expose higher LST due to east-west sun exposure.
Contextual Cooling Solutions: Urban form-based codes can offer targeted cooling solutions. Diverse zones with customized regulations—shaded walkways, cool roofs, or high EVC—can cater to varied needs.

Way Forward

Incorporating Learning: Urban planning must integrate findings from the study into building by-laws and master plans. Pune’s experience showcases the impact of SVF, aspect ratio, EVC, and urban morphology on heat gain.
Adaptation for Other Cities: Each city may face distinct drivers influencing heat resilience, necessitating customized solutions and urban planning modifications.
Economic Benefits: A 1°C temperature reduction corresponds to a 2% drop in the city’s power consumption, highlighting the financial advantages of heat mitigation strategies.

Role of Urban Form in Heat Resilience