Anuradha Adhikari of ICLEI Local Governments for Sustainability South Asia (ICLEI South Asia) and Nilesh Prajapati (GFA Consulting Group GmbH) share recommendations for reducing the urban heat island effect in Rajkot, India, providing an example for other cities. 

Rapid urbanisation and global climate change are contributing to the urban heat island (UHI) effect in cities across the world. Typically occurring due to a combination of increasing temperatures and increasingly built-up areas, the effect is becoming a cause of particular concern for cities in hot dry climates. In Rajkot, a combination of urban growth and climate patterns has resulted in a UHI effect where the city regularly experiences higher temperatures than the surrounding or outlying areas.  

Rajkot is located in a semi-arid zone, where summers are very hot and dry - temperatures range between 24°C and 42°C. Between 1972 and 2021, data from the Indian Meteorological Department Rajkot office shows that 28 years had less rainfall than the average 745mm per annum. Added to this, the Climate Smart Cities Assessment Framework 2.0 reported that between 2011 and 2020, Rajkot grew spatially by 54% and demographically by 40%. 

To address the UHI effect in the city, the Rajkot Municipal Corporation (RMC) has begun to develop city-level recommendations and solutions for urban cooling, becoming a pioneer in India for local action on urban heat. ICLEI South Asia, with assistance from the United Nations Environment Programme (UNEP), has supported the RMC to identify and implement interventions to tackle urban heat, and to provide the framework for an Urban Cooling Plan. The aim is to ensure a thermally comfortable environment for the city’s residents.  

An analytical review of existing national, subnational and city-level plans, policies, standards and guidelines, and strategic consultations with a range of stakeholders (e.g. administrative bodies, distribution companies, builders’ associations, the Industrial Development Corporation, the Indian Green Building Council and civil society representatives) supported the development of the sustainable urban cooling framework.  

Technical assessments followed, using satellite imagery to develop a day-night, seasonal surface thermal profile and identify hot and cool spots. For example, for May, the hottest month in Rajkot, hotspots were classified as locations with a land surface temperature (LST) consistently higher than the median surface temperature of 39.5° C, and cool spots were consistently lower. A thermal sensor-mounted drone then gathered micro-level data about land use features in four neighbourhoods in hotspot areas, including built-up forms, the type of surface materials used, and their emissivity. All four areas had residential, industrial and greenfield sites, and traffic junctions. 

Causes of the UHI effect in Rajkot 

Changes in land use and land cover, building density, construction practices and commonly used building materials significantly influence how urban areas experience and retain heat. Conventional urban building materials used in Rajkot, such as concrete roofing, galvanised iron sheets, reinforced cement concrete, metal sheets coated in blue, green and silver, and bitumen-coated roofing, were found to trap more heat. Areas where these were the predominantly-used materials were 2-3°C hotter compared to areas where alternative materials were used, such as reflective roofing, roofs with white paint, green matting or solar panels.  

The neighbourhood-level analysis showed how areas with the least vegetation cover had the highest proportion of hot spots and the cooling effect of green cover was evident on asphalt roads – those with tree cover nearby had a 3°C lower LST compared to those with no tree cover. High-density commercial and industrial areas as well as major traffic junctions also contributed to both day and night atmospheric temperature hot spots. Areas without tree canopies or water bodies nearby had a 2-3°C higher night-time temperature, as they lacked the cooling effect of green and blue spaces.

“Blue and green spaces are natural and semi-natural areas within a city or urban area that could include parks, gardens, rivers and lakes.” 

Challenges 

The review identified some of the main challenges to addressing the UHI effect in Rajkot. These included:  

• A lack of awareness regarding UHIs and technical capacity in the town planning department hindering effective planning.   

• A lack of awareness among buyers about the life-cycle costs and benefits of energy efficient buildings, resulting in minimal demand and making construction unviable. 

• Poor implementation of existing regulations and guidelines due to procedural complexities. 

• An inherent lack of coordination and collaboration among different external agencies with the municipal corporation around work on urban heat.  

The existing voluntary certifications or mandatory standards to promote building-level urban cooling, are not financially viable for real estate projects, nor do they align with the existing procurement policies that emphasise selection based on lowest cost instead of prioritising best technology. Inherent complexities in the reward schemes for promoting energy efficient construction also limit the widespread adoption of guidelines such as the Energy Conservation Building Code (ECBC), 2017. For example, the process for owners and developers to access the incentives provided by the General Development Control Regulations (GDCR) is obscure, lengthy, and consequently off-putting.  

At an urban planning level, existing policy and regulatory measures are not consistently enforced. For example, the Urban Greening Guidelines, 2014 prepared by India’s Ministry of Housing and Urban Development (MoUD) (now the Ministry of Housing and Urban Affairs (MoHUA)) recommend that a minimum of 20% of a city’s geographical area should have green cover. In Rajkot, at the time of assessment, green space represented just 2% of the city’s area. On the other hand, planning instruments such as the Town Planning (TP) Scheme do not always contain specific guidelines for green cover. The TP Scheme focuses on smaller areas for targeted development across the city by defining different land uses in different zones. After allocating roads and other public services, barely 3% is allotted for green cover.   

The Town Planning Scheme is the micro-level planning process for pooling together all the land under different ownerships and redistributing it in a properly reconstituted form after deducting the land required for open spaces, social infrastructure, services, housing for the economically weaker section, and road network. This process enables the local authority to develop land without fully acquiring it and gives it positive control over the design and timing of the urban growth. 

Formulating a TP Scheme is a long process that does not always match the pace of development in adjacent areas and there can be a lack of available, continuous land parcels that align with the heat island pockets and that can be used effectively to establish green and blue infrastructure. Once it is finalised, RMC has limited control over the actual utilisation of a land parcel and the type of buildings to be constructed.  

Added to that, the concentrated development of high-rise and dense buildings, promoted by Transit Oriented Development creates impervious concrete structures that restrict the free flow of air, and absorb and re-emit more heat than a natural landscape, adding to the UHI effect. 

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Opportunities for urban cooling in Rajkot 

ICLEI South Asia’s review suggests that target-oriented urban design and planning interventions to promote urban cooling actions are needed. These should be supported by robust institutional mechanisms, multistakeholder integration and capacity strengthening to improve understanding of the UHI effect and possible actions to address it. In addition, administrative bodies should leverage finance to assess and adopt emerging technologies, such as district cooling infrastructure, and establish monitoring mechanisms to ensure that the plan translates into effective, scaled implementation. 

It also identified some specific initiatives and actions that could be taken: 

• Using low-cost, reflective white paint or reflective roofing material (e.g. China mosaic, white ceramic tiles and stone for new social housing schemes, hawkers’ zones and vegetable markets);  

• Using solar panels on institutional buildings; 

• Using light-coloured reflective paints or reinforced grass to reduce the pavement temperature; 

• Aligning buildings with the wind direction, with sufficient space between them to allow wind flow at natural speeds; 

• Integrating and enhancing nature-based solutions such as evaporative cooling from water bodies; 

• Finalising the TP Scheme before development, factoring in the wind direction and location of barren land to appropriately allocate blue-green spaces; 

• Having a specific provision in the General Development Control Regulations to reserve and include recreational green spaces in shared or common residential and commercial plots; and 

• Using passive cooling measures (e.g. building orientation, insulation, natural ventilation and shading), energy efficient air conditioning and other home appliances, and having guidelines for positioning air conditioning units to minimise the impact of exhaust heat. 

There were recommendations for the Smart City Area and upcoming TP Schemes as well. It is proposed that a minimum of 5% or more green cover is allocated in upcoming RMC TP Schemes, and 80% of buildings in the Smart City Area will be constructed as green buildings by maximising the use of energy-efficient appliances and renewable energy. 

Initiatives to reduce the UHI effect in Rajkot are still at a nascent stage. However, the process of developing an Urban Cooling Plan and the recommendations for other planning documents, shows that there is great potential for RMC and other city governments to address and find solutions to the thermal discomfort often experienced in urban areas in India and beyond.