The summer in Ahmedabad has always been the stuff of legend. And this year is no different. Barely 10 days into March, the India Meteorological Department (IMD) issued a red alert for heat wave. By mid-April, several yellow and orange alerts had been issued. May, too, is predicted to bring in no solace.
As they wipe sweat off their brows, Ahmedabad residents can take heart from revelations of satellite maps, which have shown that the city has got cooler by 2-3 degrees over the last five years, across all the wards. The coolest among them is the Paldi area, which is on the western bank of Sabarmati River in the heart of the city.
A man walks by the street in Ahmedabad on a scorching summer afternoon (Express/Bhupendra Rana)
Other relatively cooler wards were Navrangpura, Sardar Patel Stadium, Vasna, Maninagar, Ghatlodia and Naranpura. Barring the exception of Ghatlodia and Naranpura, these localities have one thing in common – they are largely residential in nature and are located next to major water bodies, either the Sabarmati River or Kankaria lake.
The heat map of Ahmedabad City and nearby townships was imaged using NASA’s Landsat 8 satellite by measuring land surface temperature (LST), down to the ward level of the city. Imaging carried out at 5.38 pm on May 24, 2024, and compared with those taken at the same time on May 21, 2020, show that the LST of Ahmedabad has decreased by 2-3 degrees Celsius in all the 48 municipal wards of the city area that are divided into seven zones.
The relative coolness coincides with the increase in green cover of the city from 10% to 12.5%.
Ahmedabad is spread over a 480 sq km area. Substantial green cover in the city expanded from 48.98 sq km in 2021 to cover 60.1 sq km area in 2024, said data from International Council for Local Environmental Initiatives (ICLEI), a network of local and regional governments committed to sustainable development.
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Tree density per person has also increased in Ahmedabad, said data from ICLEI South Asia, which provides technical support to the Ahmedabad Municipal Corporation (AMC) for climate resilient development.
Ankit Makvana, Senior Manager, Gujarat Operations, ICLEI South Asia, said that tree cover in the city had increased in 41 of 48 wards between 2021 and 2024.
Deputy Municipal Commissioner, AMC, confirmed that over the last 12 years, between 2012 and 2024, tree cover has substantially risen to include 20-30% of ward area in Thaltej and Sardarnagar alone.
AMC Commissioner Banchha Nidhi Pani said, “While the corporation is doing its bit, all citizens must also join in the effort to make our city greener.”
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Abhiyant Tiwari, Lead of Climate Resilience and Health at Natural Resource Defence Council (NRDC) India, a New Delhi-based private company working on climate resilience, renewable energy, cooling and clean transport, said enhancing the green cover has proven to mitigate heat and reduce the Urban Heat Island (UHI) effect.
Proximity to water bodies was another reason as some of the coolest wards in the city, both in 2020 and 2024, were next to two major water bodies. These included Navrangpura, Paldi, Vasna, SP Stadium, and Jamalpur.
The authorities, meanwhile, are on their guard.
With the temperatures expected to only rise with each year, Ahmedabad has activated its yearly measures under the Heat Action Plan (HAP), which includes setting up drinking water stations, shades, leaving public gardens open for longer hours, turning off traffic signals during hours of extreme heat, and restricting manual labour on days with heat wave warnings.
Satellite images accessed by The Indian Express show the scale of heat generated by the UHI effect in Ahmedabad, which leaves large portions of its populace vulnerable to extreme heat.
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What are urban heat islands
Urban heat islands or UHIs are areas, which experience higher heat loads than their surrounding areas. Data reveal how areas that were either close to water bodies like the Sabarmati River or a large lake like Kankaria in Maninagar, were less hot. It also indicates how tree cover can make a difference.
Earlier, expert studies had shown how younger Ahmedabad residents can “tolerate” high temperatures, in the range of 22.6-32.6 degrees Celsius, even as senior citizens were more susceptible to heat-related ailments.
In its budget for 2025-26, the AMC approved an allocation of Rs 50 lakh to identify UHIs and take steps to mitigate its impacts.
Dr Tejas Shah, the Deputy Health Officer in charge of the HAP, told The Indian Express, “We are already getting data of ward-wise temperatures in Ahmedabad. What we are planning to do now is find an appropriate research partner to study mitigation measures that can be suited to each area to decrease the UHI effect across various parts of the city.”
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How heat affects the heart, and brain
“The people of Ahmedabad are exposed to heat stress or, sometimes, extreme heat stress, during the summers, which increases the risk of heat stroke and associated conditions like dehydration and chronic cardiovascular diseases. Extreme temperatures can also impede cognitive abilities, impacting productivity and focus,” said Dr Jaidevi Jeyaraman, Associate Professor at the Institute of Infrastructure Technology Research and Management (IITRAM) in Ahmedabad. “In such situations, it becomes crucial to guarantee that outdoor spaces are thermally comfortable and effectively cater to the needs of pedestrians, contributing significantly to the overall quality of urban living and comfortable walking spaces,” she added.
Dr Jeyaraman and others conducted a study on the perceptions of outdoor thermal comfort on pedestrians of Ahmedabad through bio-meteorological measurements during all three major seasons. This study, which covered 1,620 people in 2022-23 and was published in the International Journal of Biometeorology, found, “The people of Ahmedabad are tolerant towards warmer temperatures… The air temperature when respondents were feeling thermally neutral was 27.6 degrees C, and the air temperature range in which the respondents were feeling thermally comfortable was between 22.6 degrees C and 32.6 degrees C. The wider comfortable band of about 10 degrees C indicates that the people of Ahmedabad have tolerance towards wide air temperatures.”
Her baby in arm, a woman covers herself with a dupatta (Express/Bhupendra Rana)
However, “The neutral air temperature for age groups of those younger than 30 years was slightly less than age groups of 31-45 years and those older than 45 years, making them less tolerant to higher temperatures. Younger people being habituated to ACs at lower set-points could be a reason for this,” said Dr Jeyaraman.
The study noted that with temperatures in Ahmedabad being as high as 45 degrees C during summers, bringing it down by nature-based solutions and other mitigation measures could prevent heatwaves and other related risks.
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Vulnerable group in urban areas at higher risk
Tiwari of NRDC India said people, especially vulnerable groups living in urban areas, experience higher heat stress, resulting in higher heat-related health issues compared to those living in peri-urban or rural areas. “This happens due to UHI effect, which amplifies the intensity and duration of high temperatures during the heatwaves as increased built environment, concretisation, human activities, and reduced green cover, permeable ground surfaces, and water bodies trap the heat in the cities and make them relatively warmer. This also adds up to an increased demand of energy for cooling,” Tiwari added.
The impact of UHIs on human health was discussed in research papers presented at the Indo-US Conference on Climate Change Impacts on Occupational and Environmental Health (CliCON-OEH 2025) held in Ahmedabad on February 26-28 earlier this year.
Excerpts from the abstract for a systematic review of global studies on UHI effect and its impact on Heat-Related Morbidity and Mortality, by Ekta Ram and others at the National Institute of Occupational Health (ICMR-NIOH), said, “Four studies identified that the elderly population (65+) is particularly susceptible to cardiovascular and respiratory conditions during heatwaves. One study documenting a 4.06% annual increase in heat-related mortality from 2000 to 2010 attributed (it) to UHI, with projections indicating a three-fold rise by 2080.”
Similarly, the primary findings from another systematic review underway at Pushpagiri Institute of Medical Sciences and Research Centre in Kerala by Chinnu Sara Varughese and others, on the impact of UHIs in India, stated, “UHI areas are increasing across the country, with significant decrease in thermal comfort, increased heat-related health risk, mortality and outbreak of infectious and vector-borne diseases… Evidence from this review suggests that UHIs affect human health in India, thus requiring appropriate urban planning and heat mitigation strategies.”
A man takes a drink of water as his friend, head wrapped in a scarf, looks on (Express/Bhupendra Rana)
Land surface temperature vs air temperature
Vidhee Avashia, a Post-Doctoral Researcher at IIM Ahmedabad, said, “Land-use changes play a major role in determining temperatures in specific localities in a city. As the climate changes and temperatures rise, the influence of such variations will become more intense. Further, the increase in nighttime temperatures, wherein during heat waves a city experiences hot day/hot night events when the human body does not get enough cooling time, the role of land use becomes even more important. This ‘land use’ is captured as the land surface temperature (LST).”
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She said there are very few monitoring stations to measure air temperature, especially in developing and low-income countries where these stations are costlier to install and run. Meteorological data is largely based on air temperature.
In their paper, “Understanding temperature related health risk in context of urban land use changes” published in the Journal of Landscape and Urban Planning, in 2021, Avashia and others drew a link between more buildings and developed/constructed land and higher chance of heat-related deaths. “For every 1% increase in constructed spaces and concrete surfaces, the relative risk of death due to heat rises by 0.59 points at 40°C and 0.78 points at 45°C,” the study noted.
Shade-installation work in progress at Sabarmati Riverfront in Ahmedabad (Express/Bhupendra Rana)
Need of the hour: Heat health information
Dr Dileep Mavalankar, former Director of the Indian Institute of Public Health Gandhinagar (IIPHG), who was instrumental in developing the first Heat Action Plan in Asia, for the city of Ahmedabad, said, “It is necessary to give the people proper information on temperatures through the day and night. It is also important to give information about hot nights. Our 15-year study shows that if the day temperature is 45 degrees and night temperature is below 28 degrees, there isn’t much mortality. But if, under the same circumstances, night temperature goes up to 30 degrees, mortality increases. In UHIs, the night temperature is also high.”
Dr Mavalankar said that like other disasters, the urban local bodies should declare “all cause death data” daily during the summer months. “This will not only help in cautioning people at large, but will also assist in formulating policy to mitigate deaths caused directly and indirectly by the heat,” he added.
A man walks by the street in Ahmedabad on a scorching summer afternoon (Express/Bhupendra Rana)
Her baby in arm, a woman covers herself with a dupatta (Express/Bhupendra Rana)
A pair of spotted owlets rest on a tree on a scorching summer day at Sayaji Baug Zoo in Vadodara (Express/Bhupendra Rana)
A man takes a drink of water as his friend, head wrapped in a scarf, looks on (Express/Bhupendra Rana)
Shade-installation work in progress at Sabarmati Riverfront in Ahmedabad (Express/Bhupendra Rana)