Delhi’s rising temperatures are causing severe heat stress, impacting public health, livelihoods and infrastructure.
Vulnerable groups, including the poor and outdoor workers, face the brunt of the crisis.
The city needs to prioritise long-term solutions like increasing green spaces and climate-appropriate design in buildings and public places.
Delhi has been witnessing scorching summers in the recent years. Winters and spring have also been warm, with average maximum temperatures 3°C higher than normal.
2025 saw the warmest February and March on record, while the India Meteorological Department issued heatwave alerts several times in the following months. 2024 saw one of the worst summers with temperatures soaring well above 45°C for several days.
A decadal assessment (2015-24) by Delhi-based think tank Centre for Science and Environment (CSE) revealed that Delhi temperatures departed from its normal on 42 out of 50 occasions in the summer months (March to July).
Therefore, hotter summers are here to stay. This impacts not just only public health but also livelihoods, productivity, infrastructure and the environment severely.
An ongoing CSE assessment has revealed that almost 76 per cent of Delhi has been facing heat stress during the summer months (April, May, June) since a decade, from 2015 to 2024. Heat stressed areas witnessed land surface temperatures above 45°C in more than six years during the decade, the study showed.
Although almost the whole city experiences intense heat annually, the south-western region of Delhi is the most affected by heat stress. This includes localities like Najafgarh, Palam, Dwarka, IGI Airport and Mahipalpur, Uttam Nagar and Dabri. This is followed by western and north-western Delhi including localities like Patel Nagar, Moti Nagar, Rajouri Garden, Vikas Puri and Nangloi in the west and Rohini, Samaypur Badli, Bhalaswa, Azadpur and Narela Subcity in the north-west. Most of these locations are peripheral.
Nearly the entire Old Delhi area is heat stressed as well as other key central areas like Connaught Place, New Delhi Railway Station, Pragati Maidan, Bharat Mandapam and Indraprastha. In the south, Okhla, Tughlakabad, Khanpur, Sangam Vihar and Jaitpur, and in the east Ghazipur, Gharoli, Patparganj, Anand Vihar, Shahdara and Shiv Vihar are heat stressed.
Interestingly, key corridors of the city, such as Grand Trunk Road, Rohtak Road, Kirti Nagar-Mayapuri road, and a majority of the Ring Road are also heat-stressed. While this is largely due to the dark bitumen which traps heat from the sun when exposed, the other reason is traffic (vehicle exhaust) and the vehicle themselves that trap heat in their metal body. Traffic congestion points are anthropogenic heat sources.
Areas that are not heat-stressed have heat sinks in the forms of ridges, green belts, district parks, river Yamuna. and other sizeable green and blue features.
A ward-wise drill-down (as per Census 2011 data) of heat stress has revealed that 10 wards have 100 per cent of their area under heat stress. These are Bazar Sitaram, Ballimaran, Kucha Pandit, Turkman Gate in Old Delhi, Milap Nagar and Madhu Vihar in West Delhi, and Babar Pur, Karawal Nagar East, Tukhmir Pur and Nehru Vihar in East Delhi. Nearly 0.55 million people live in these wards. These wards are quite dense and do not have any green space or a water body nearby.
Further, 78 wards have more than 90 per cent of their area under heat stress. The Census 2011 had recorded that these wards were home to 4.59 million people. The number would be much higher by now. The average green cover in these heat-stressed areas is less than 1.5 per cent, according to the CSE analysis.
Only 23 wards enjoy some relief, with less than 25 per cent area heat-stressed, according land surface temperature (LST) satellite imagery. Some of these wards are New Delhi Municipal Corporation Charge 4 and 5, Geeta Colony, GTB Nagar, Malviya Nagar, Shahpur Jat, Chittaranjan Park, Preet Vihar, Mehrauli, Pushp Vihar, Majnu ka Tila, Munirka, Lado Sarai, among others. All of these wards have either a district park, ridge or river Yamuna in their vicinity. This reinforces the need to work on increasing green and blue spaces across the city.
Extreme heat does not affect everyone in the same manner. There are certain demographic groups that are more vulnerable to high temperatures than others due to physiological disadvantage or co-morbidities. This includes children, elderly and women.
Others are less privileged to cope with the rising heat and lack resources to adapt such as access to basic services, active cooling solutions, and have a locational and occupational disadvantage. This group includes the poor, homeless and people who work outdoors like construction workers, street vendors, artisans, automobile mechanics, ragpickers, sanitation workers and gig workers, among others.
These population groups constitute a substantial proportion of the urban economy, especially in large cities. For instance, 80 per cent of the workforce in Delhi is employed under informal arrangements, according to an analysis conducted by global labour rights group Women in Informal Employment Globalizing & Organizing, based on the 2017-18 Periodic Labour Force Survey data compiled by the National Sample Survey Organisation.
CSE conducted a ward-level assessment with seven identified vulnerable groups — construction workers, street vendors, residents of informal settlements (JJ bastis), homeless, children (0-9 years), women and elderly (60 years and above) — to determine how many individuals from each group are located in heat-stressed areas in Delhi. This spatial distribution gave both the concentration of specific group in a ward, as well as a cumulative overview of all groups combined ward-wise.
The cumulative assessment reveals that nearly a third of the wards in Delhi fall within the moderate to very high vulnerability categories. Matiala is the only ward that falls in Very High vulnerability category, with more than 80 per cent of their areas under heat stress. Kakraula, Hastsal, Chandni Chowk, Mukund Pur, Kunwar Singh Nagar, Narela, Ballimaran, Mohan Garden, Jama Masjid, Bawana, Rohini, Sahibabad Daulat Pur, Pooth Kalan, Burari wards fall under High vulnerability. Many wards located at the city periphery and the walled city of Delhi show moderate vulnerability.
This cumulative vulnerability index, to be published in the following days, informs the areas that need urgent action due to both lack of safeguards and high presence of vulnerable people. The strategy for heat resilience in Delhi needs to address both these aspects in emergency response as well as long-term mitigation.
Assessments like this have now become crucial, as some areas need more attention as compared to the others. This is not only due to their physical conditions and extreme heat, but also because they house more vulnerable groups than others. These hotspots must be prioritised in heat actions that should focus on building resilience for a long-term and not just ad-hoc treatment in heatwave periods.
Unfortunately, a majority of cities which are at a high heat risk, including Delhi, focus on short-term emergency measures. A recent study by Delhi-based independent research organisation Sustainable Futures Collaborative revealed that cities are mainly implementing measures like access to drinking water, changing work schedules and boosting hospital capacity before or during a heatwave. This is done because of little expense of such measures, whereas a shift to long-term measures calls for dedicated fiscal resources, according to the study.
Also, all long-term measures that exist in these city plans are confined to training of health workers and systems to monitor heat related deaths, the researchers noted. Measures to build heat resilience through appropriate urban planning are absent.
Delhi Heat Wave Action plan 2025 has floated a pilot on cool-roofs at Delhi Secretariat, Kashmere Gate ISBT and Anand Vihar ISBT. Such initiatives are needed more at the settlements of the poor, along with improved access to safe water and sanitation.
The plan has brought to the table long-term solutions like increasing green cover in the city and promoting passive design in buildings. But these will remain vague until the master plan of Delhi and building bye-laws incorporate such elements.
So, how to build heat resilience — with focus on vulnerable groups?
Urban planning and design form the core of long-term solutions to build heat resilience in cities. But before this, ward-level (or smallest possible demographic entity) vulnerability assessment is crucial. This helps prioritise heat action for the most vulnerable groups in locations with high heat exposure.
The CSE assessment has looked at wards that have high concentration of the seven identified vulnerable groups along with high heat exposure, highlighting the need for priority action in these wards. Many of these wards lack natural safeguards, therefore retrofitting of buildings and busy public places with passive cooling solutions needs to be mobilised.
This includes installation of shading devices in public places, use of light coloured reflective paint / finish on facades and roofs, use of overhangs on south and west facades to cut heat gain, shading windows and roofs using sunblinds, canvas or shade nets, cool and green roofs in public buildings, and switching to solar rooftop.
Cool roof programmes targeting buildings in vulnerable wards and informal settlements need to be prioritised. Providing insulation by polyurethane foam insulated panels, or spray foam, bamboo mats, fibreglass mats inside metal roofs of inhabited structures and paints with high solar reflective index can reduce the indoor temperature.
Cool roofs can lower indoor temperatures by up to 5°C. Further, basic services like provision of safe water, toilets, primary healthcare facilities must be ensured in these wards ahead of the peak heat season.
In addition, vulnerable group-specific measures are also essential. In the case of heat emergency, solutions like staggered timing, potable water and toilets at workplaces and public places, provision of shaded resting areas and community cooling centres for outdoor workers, temporary passive cooled shelter for homeless, emergency relief kits and modified standard operating procedures at workplaces during high temperatures become important for them.
The CSE assessment showed that green spaces and water bodies are the ultimate safeguards against heat. Measures like increasing tree cover and pervious surfaces in the city, while shading streets, public places and parking lots so that the roads and paved surfaces do not trap a lot of heat are long-term solutions.
Elements of water like bio-swales, rain gardens, fountains, especially in busy commercial areas or central business districts improve microclimate to a great extent. Water-sensitive urban design and planning, combined with active systems like evaporative wind towers, have the potential to reduce ambient temperature by 3-8°C.
Guidance on passive design techniques that include shading, insulation and ventilation must be made public so that people can take deliberate action to cool down their homes and reduce dependence on air conditioners that further heat up the environment. Integration of these cooling techniques with master plan and building bye-laws is crucial to eliminate bad planning in new developments and redevelopments and to ensure a climate-responsive built environment.
These solutions can be supported with dedicated funds like Delhi Building and Other Construction Workers Welfare fund, Town Vending Committee fund for street vendors. Technology innovation grant under Pradhan Mantri Awas Yojana 2.0 can help in retrofitting for affordable housing for vulnerable groups. City-wide funds such as adaptation funds and innovative instruments like climate bonds, parametric insurance are also viable options.
Measures like improving healthcare, public transportation, early-warning systems, public awareness on the dos and don'ts during heatwave, self-diagnosis for heat-related illness and treatment, capacity building of healthcare, emergency services and municipal staff should also be done regularly.