Urban planning must factor in wind flows to curb heat stress in Indian cities

UPDATE - follow-up to Letting the wind flow freely is the secret to cooling our cities: Ground-level wind speeds in urban areas continue to slow down due to dense high-rise construction, highlighting the urgent need for ventilation-focused city planning. Dense urban infrastructure and high-rise buildings disrupt natural wind flow and create surface friction, which slows down winds near the pedestrian level roughly 10 meters from the ground.

Urban Design Factors

Amruthraj M.N., a consultant with the Sustainable Energy Lab at the Indian Institute for Human Settlements in Bengaluru, points out that structures like high compound walls and podiums block previously defined wind corridors. Aaron Serre, a meteorologist from the University of Alabama in Huntsville, adds that replacing vegetation with asphalt and concrete cuts down evapotranspiration and worsens the urban heat island effect.

Scientific Challenges

Prasad Vaidya, a senior adviser at the Indian Institute for Human Settlements, notes that computer-based simulations like computational fluid dynamics can analyze fluid behavior, but they are expensive and complex to implement. Meanwhile, Yugank Goyal from IIM Ahmedabad suggests creating homogenized wind records and using satellite imagery to build city ventilation maps.

Context

Terrestrial stilling, the global drop in near-surface wind speeds observed since the 1980s, compounds urban heat stress when combined with the loss of trees and water bodies. Integrating wind and ventilation studies into city master plans remains a key challenge for rapidly growing metropolitan areas.