The Micro-climate in the Streetscapes of India
“In a city the street must be supreme. It is the first institution of the city. Today, streets are disinterested movements not at all belonging to the houses that front them. So you have no streets. You have roads, but you have no streets” – Louis Kahn
As summer gets closer every second, we could feel the angry, burning sun dawning over us, forcing us to seek the help of air conditioners and coolers every other minute. Yet, every now and then, we come across spaces which are much cooler compared to the boiling heat wave roaming the city. Curious, isn’t it? And if this isn’t shocking enough, what if I tell you that this kind of a cool blanket can be seen often in the streets of Rajasthan?
Microclimate! Microclimate is the climate of a small area that is significantly different from the overall climate of the region. So, even though there might be a rise in temperature in the overall region, one might find a change in the respective area. However, this difference can be seen under both spectrum – positive or negative.
Positive Microclimate is having the overall atmosphere better suited to the ecology and the people. For example, a cool climate in an extremely hot area, or a pleasant warm atmosphere in a cold snowy region is welcome. But Negative Microclimate is the overall region affected poorly due to the impact of human intervention; say, Urban Heat Island (UHI) caused by Urbanization. Nonetheless, it is undeniable that human intervention is the cause for both the cases – be it positive or negative.
Streets are the roots that branch out as a city; molding it as a place for existence to the current and the future generation to lead a quality life. Often, when we walk into a street, we observe a different atmosphere based on tangible elements (Architecture, materials, proportions, spacing, flora and fauna) and intangible elements (water, light, shadows) and though wide canopy trees help in minimizing the UHI by cutting down the heat, a study was carried out to check the role of the relation of the softscape elements with the hardscape elements.
The portion of the pavement that receives direct radiation i.e. without seeping through a softscape barrier radiates more heat than the portion that receives indirect radiation. It was also analyzed that just the presence of plants alone does not support a positive microclimate. Reducing the usage of inappropriate pavers like solid pavers which receive, absorb and radiate a lot more heat, compared to perforated pavers, using climatically responsive materials, selection of plants, the geometry of the streetscape, all of these collectively play a significant role in reducing the temperature of the region.
Given our Indian context, a fascinating example for microclimate are the streetscapes of Rajasthan. Rajasthan is located in the western part of India. It is the home of extremely harsh climatic conditions with very little vegetation or water and the climate is hot and dry. Likewise, the streets are ancient and fluid. But, when one walks in the streets of Rajasthan, the narrative of the person is quite different, despite being built organically without a master plan.
In this streetscape, it is observed that the streets are considerably a few degrees cooler than the overall temperature of the region. This is due to the proportion of the houses and the buildings in the street. The overall height-width ratio is an important parameter in the streetscape ventilation.
The buildings lining the streets on both sides are row-houses up to two or sometimes three storeys high, and often have a shared wall between two buildings; the width of the street is generally narrow (not more than 8m wide); the shadows of the buildings fall onto the street and the opposite buildings – thus always shading it from the harsh overhead sun.
The walls of the houses are thick and are made with local climate-responsive materials such as stones or mud and frequently finished with lime plasters as the light-coloured plaster of the thick external walls prevent the absorption and radiation from the boiling sun; keeping the interior and the exterior of the houses cool. The houses also have semi-open spaces outside to be used as leisure spaces to relax or for commercial settings – a shop or storing materials. The inhabitants also practice sprinkling water outside the houses to cool the temperature around the house and to also increase the humidity. Occasionally, a few trees are present in the streets which apart from embellishing, also alter the microclimate of the area.
Since every house on both sides of the street follows this in harmony, the street archives a microclimate which is significantly cooler than the average microclimate of the region. The temperature of the street is pleasant as it’s down by a few degrees, making the air sufficiently cool and moist.
In contrast to the traditional streets of Rajasthan, the urban streets in cities have a stark difference. They are usually extremely hot and unpleasant. However, one can always find a few streets in cities which hold a splendid exception.
A study on the temperature variation in the Chennai Metropolitan area showed that the right balance of buildings and vegetation that shadow the narrow streets reduce the daytime temperature of the region. One visible example is the streets in Besant Nagar and Adyar; they demonstrate a good balance of elements of urbanism in a streetscape. The quiet human-scale street leading to the beach, the shady vegetation and the residences snugged in trees, it’s quite an enjoyable haven in a city like Chennai. Such streets also promote lots of activities and social movements therefore impacting a multitude of entities such as security, crime, well-being and health.
Streetscapes are the cores of our social and economical life. With the architectural wealth in India, certain principles of design can be learnt and reflected with enthusiasm at planning levels which will help alter the microclimate and make spaces more habitable, a pleasure to live in and add life to the aspiration of Kahn.
- Hidayat, I.W., 2010, The Ecological Role of Trees and their Interactions in Forming the Microclimate Amenity of Environment, Jurnal Bumi Lestari, Volume 10 No. 2, Augustus 2010, hlm
- S. Anupriyaa, Exploratory Study on the relation between Urban Landscapes and Urban Corridors for Outdoor Thermal Comfort.
- Lilly Rose Amirtham, Urbanization and its impact on Urban Heat Island Intensity in Chennai Metropolitan Area, Sathyabama University, Chennai.