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Cse In News

The tell-tale signs of urban heat stress

Tap water is boiling hot and air conditioners are not having the desired effect. Such is the severity of the Indian summer this year, that even at night, cities in the northern plains are not cooling down. The relentless heat wave, with little to no rainfall, is exacerbated by the Urban Heat Island phenomena, a byproduct of climate change and excessive urban infrastructure. A recent study by the Centre for Science and Environment (CSE) titled ‘Decoding the Urban Heat Stress among Indian cities’, tracked data in 6 major cities - Bengaluru, Chennai, Delhi, Hyderabad, Kolkata and Mumbai – and suggested urgent measures to protect public health. While a heat index of 41° C is considered dangerous for human health, temperatures in Delhi have been hovering over that for most part of this season, rendering the Urban Heat Island phenomena stronger at night. “Hot nights are as dangerous as mid-day peak temperatures. People get little chance to recover from day-time heat if temperatures remain high overnight. A study published in the Lancet Planetary Health has noted that the risk of death from excessively hot nights would increase nearly six-fold in future,” said Avikal Somvanshi, Senior Programme Manager, Urban Lab, CSE. Deadly combo The heat stress is not just about rising temperatures. It is a deadly combination of air temperature, land surface temperature and relative humidity that leads to acute thermal discomfort and heat stress in cities, according to the CSE report. With exception of Bengaluru, in all five cities studied by CSE, rising humidity levels have worsened the heat stress. a heat index of 41°C is considered dangerous for human health a heat index of 41°C is considered dangerous for human health | Photo Credit: ANINDITO MUKHERJEE Trends in heat stress will further worsen in cities with climate change, according to the Intergovernmental Panel on Climate Change (IPCC), Working Group-I, Sixth Assessment Report (AR6 WG-I). This is due to reduced ventilation, heat trapping by closely spaced tall buildings, heat generated directly from human activities, heat-absorbing properties of concrete and urban building materials, and limited vegetation.  Action plans According to CSE, heat management action plans are urgently needed to expand green areas and waterbodies, reduce thermal load on buildings and improve thermal comfort, and implement emergency measures during heat wave episodes to protect public health.  India is not the only country facing the brunt of a severe heatwave. Leading athletes, Olympic champions and scientists in a report called ‘Rings of Fire’, have warned that intense heat at the Paris Olympics 2024 could pose a serious threat to the well-being of participants.

Climate change: Volcanic eruption of heatwaves

This summer has seen among the longest prolonged heatwave periods in India’s meteorological history. Soaring temperatures of 45-50°C - some places reported over 50°C - continued for over a month in May and June in the Northwest region. Multiple fire accidents during the same period added to the distress, severely taking its toll on the health and medical infrastructure of the country. The record breaking spell of excess heatwaves created a domino effect and a perfect storm for a series of disasters. It all began with the massive wildfires in Uttarakhand and Himachal Pradesh, affecting the quality of air and increasing the heat-trapping greenhouse gases. Frequent incidents of fire in hospitals and high rises followed, leading to unfortunate loss of lives. The demand for electricity to run cooling equipment shot up like never before. And Delhi is witnessing an unprecedented drinking water crisis. Urban heat island The rise in the number of migrant populations in urban areas led to an increase in unplanned urbanisation. Buildings came up in encroached forest areas and water bodies, which are essential for regulating heat in urban areas. For instance, in the 1970s, there were over 200 water bodies in Delhi and its surrounding areas. Now, only 20 such lakes exist. Consequently, cities have turned into urban heat islands where buildings, roads and other infrastructures absorb and re-emit heat, making the urban jungle several degrees hotter than the surrounding rural areas. Health emergency Recent visuals of unclaimed bodies bound in white and polybags strewn outside hospitals in Delhi-NCR due to lack of space in mortuaries captured the plight of the marginalised lot. Reports suggest that the relentless spell of heatwaves claimed multiple lives of the destitute and the homeless. The videos went viral on social media and evoked strong reactions. “Our body is not prepared for such a level of warming in this unprecedented summer heat,” says well known environmentalist Sunita Narain, Director General of the Centre for Science and Environment.

How to address water shortage in our dense unplanned settlements

How do we define a “Water Sensitive City” (WSC) or a “Climate Resilient City” with water at its core? Can it be done abstractly? It certainly cannot be defined in a way that incorporates everything without prioritising actions. In the first part of this series, we discussed the discourse on Water Sensitive Urban Design and Planning (WSUDP). Who benefits from WSUDP and how should perhaps guide the theory and practice of WSUDP or WSC framing for cities in the Global South. We then proposed the necessity of a city water and sanitation plan. This entails a long-term plan for each city, aimed at achieving water equity and justice. Identifying hotspots or problem areas for groundwater, water supply, wastewater, and stormwater will inform the development of a WSUDP or WSC vision and plan. This approach shifts focus away from individual projects and detailed project reports towards a city-wide reimagining of water supply, wastewater, and stormwater solutions. For example, a 20-year water security vision for a city could include a roadmap of interventions every five years. Read more: Delhi’s water woes: Megacity should control wastage, regulate industrial usage & address disparity to combat shortage In 2022, Delhi-based Centre for Science and Environment (CSE) proposed a water-sensitive cities framework for the Global South, identifying four parameters or indices for progress towards becoming water-sensitive. These parameters were: Functional infrastructure for water supply and sanitation (addressing breakdowns and underperformance in existing infrastructure); functional and inclusive infrastructure (ensuring accessibility for all, including the less privileged); reuse of treated wastewater and biosolids (a priority for the water, energy, and nutrient-deficient Global South, where faecal waste is a valuable resource for agriculture). CSE tested the WSC framework in 2023 through primary research in Sangam Vihar, a densely populated, unplanned urban settlement in Delhi. The aim was to understand how Delhi could achieve a water-sensitive city outcome, with equity and justice as guiding principles. Informal and unplanned settlements now dominate the urban landscape of most developing countries in Africa and Asia, especially in metropolitan cities. Water conservation and septage management can be addressed in smaller towns and peri-urban settlements through in-situ groundwater recharge and non-sewered sanitation systems. However, what about large metros and state capitals with high percentages of unplanned and informal settlements? There are many such questions that need answers: Can existing problems of low per capita water supply and high volumes of greywater, black water, and stormwater from such large, dense settlements be addressed with one-off retrofitting solutions? Is sewerage-based retrofitting to existing main sewer lines feasible for a settlement of over one million people? Further, we must ask if its water supply deficit can be met by ad hoc augmentation from existing, failing sources, considering the political economy of the water sector? Can stormwater and flooding challenges be addressed merely as drainage issues? If not, what is needed to tap into this as a water conservation resource? Read more: Securing water for Delhi: Looking beyond the numbers game The study encountered several challenges. The first was documenting the existing status of water supply, sanitation, and stormwater systems, which was complicated by the lack of data sources. Enumerating the population and their per capita water supply through a primary survey of 13 blocks was necessary. Once we clarified the population and their existing per capita water supply, we could estimate grey and black water production. We then assessed the feasibility of the sewers being laid in Sangam Vihar — the dimensions of the sewer pipes needed to convey this volume of wastewater through only two peripheral sewer lines to the main sewer line on Mehrauli Badarpur Road. REIMAGINING DECENTRALISED WATER SUPPLY FOR DELHI’S UNPLANNED SETTLEMENTS Sangam Vihar has a low water supply of 45 litres per capita per day (lpcd), far below Union Ministry of Urban Development’s Central Public Health and Environmental Engineering Organisation standard of 135 lpcd. The low volume of per capita water supply, affordability, and water quality issues have contributed to the rise of a ‘water mafia’ that controls the water supply and distribution networks. The so-called ‘water mafia’ in Sangam Vihar controls all three water supply sources: Borewells, tankers, and piped water supply. Augmenting the piped water supply can eliminate this issue. Water supply is not only very low (45 lpcd) but also highly dependent on groundwater from borewells. Any drop in groundwater levels can lead to severe water scarcity and high economic burden, as observed in the summer of 2024, when water tankers could not meet the water needs of the unplanned settlements. The 5 square kilometre area of the 13 blocks of Sangam Vihar is highly concretised and built up, hindering in-situ groundwater conservation and recharge. The forest areas on its periphery, with their small water bodies, provide opportunities for groundwater recharge. Read more: Bengaluru only needs urgent institutional makeover of its water utilities If decentralised sewage treatment plants (STP) are built around Sangam Vihar (in the peripheral forest and open areas), the treated wastewater and stormwater from area can be used to fill existing water bodies for groundwater recharge, thereby ensuring groundwater supply for non-potable purposes. ENSURING WATER EQUITY AND JUSTICE A reimagined city-wide decentralised water supply system using treated wastewater to recharge a few large lakes, allocating them for water supply to nearby areas, can ensure water equity and justice for dense, unplanned urban settlements. The CSE study mapped a 10-15 km radius of Sangam Vihar to identify large lakes and nearby STPs. Lakes exceeding 2 hectares (ha) include Hauz-i-Shamsi lake (2.85 ha), Neela Hauz lake (3.65 ha), Old Fort lake (5.30 ha), Bhardwaj lake (11.8 ha), and the largest one, Sanjay lake (74.5 ha).

‘My body can’t take it’: Brutal nighttime temperatures give Delhi residents little respite from India’s searing heatwave

Nights are getting uncomfortably and dangerously hotter in India’s capital as people in the world’s most populous nation feel little respite from unrelenting temperatures. Northern India has endured a scorching summer, with one part of Delhi reaching 49.9 degrees Celsius (121.8 degrees Fahrenheit) in late May — the capital’s highest temperature on record. But the stifling heat persists even after the blazing sun has set. The city is cooling down by only 8.5 degrees Celsius at night compared to a 12.2 degrees cooling down in urban outskirt areas, a report published by the Centre for Science and Environment (CSE) last month tracking urban heat stress in Delhi has found. The warmer nights deprive people of rest and recovery from long hours of exposure to oppressive heat, particularly for people without access to air conditioning. Bicycle rickshaw driver Sagar Mandal told CNN that he’s been getting fewer passengers because people opt for air-conditioned taxis over open-air transport. “My body can’t take it, but I have to keep cycling. We are used to physical labor, we aren’t complaining about that. But this heat is not normal, something has to change,” the 39-year-old, who pedals people around the city, said. “No one cares if we live or die, no matter who you vote for this is a problem no one can solve,” he said.

‘My body can’t take it’: Brutal nighttime temperatures give Delhi residents little respite from India’s searing heatwave

New Delhi (CNN) — Nights are getting uncomfortably and dangerously hotter in India’s capital as people in the world’s most populous nation feel little respite from unrelenting temperatures. Northern India has endured a scorching summer — with one part of the capital of Delhi recording the country’s highest-ever temperature 49.9 degrees Celsius (121.8 degrees Fahrenheit) earlier this month. But the stifling heat persists even after the blazing sun has set. The city is cooling down by only 8.5 degrees Celsius at night compared to a 12.2 degrees cooling down in urban outskirt areas, a report published by the Centre for Science and Environment (CSE) last month tracking urban heat stress in Delhi has found. The warmer nights deprive people of rest and recovery from long hours of exposure to oppressive heat, particularly for people without access to air conditioning. Bicycle rickshaw driver Sagar Mandal told CNN that he’s been getting fewer passengers because people opt for air-conditioned taxis over open-air transport. “My body can’t take it, but I have to keep cycling. We are used to physical labor, we aren’t complaining about that. But this heat is not normal, something has to change,” the 39-year-old, who pedals people around the city, said. “No one cares if we live or die, no matter who you vote for this is a problem no one can solve,” he said.

‘My body can’t take it’: Brutal nighttime temperatures give Delhi residents little respite from India’s searing heatwave

Nights are getting uncomfortably and dangerously hotter in India’s capital as people in the world’s most populous nation feel little respite from unrelenting temperatures. Northern India has endured a scorching summer, with one part of Delhi reaching 49.9 degrees Celsius (121.8 degrees Fahrenheit) in late May — the capital’s highest temperature on record. But the stifling heat persists even after the blazing sun has set. The city is cooling down by only 8.5 degrees Celsius at night compared to a 12.2 degrees cooling down in urban outskirt areas, a report published by the Centre for Science and Environment (CSE) last month tracking urban heat stress in Delhi has found. The warmer nights deprive people of rest and recovery from long hours of exposure to oppressive heat, particularly for people without access to air conditioning. Bicycle rickshaw driver Sagar Mandal told CNN that he’s been getting fewer passengers because people opt for air-conditioned taxis over open-air transport. “My body can’t take it, but I have to keep cycling. We are used to physical labor, we aren’t complaining about that. But this heat is not normal, something has to change,” the 39-year-old, who pedals people around the city, said. “No one cares if we live or die, no matter who you vote for this is a problem no one can solve,” he said.

My body can’t take it’: Brutal nighttime temperatures give Delhi residents little respite from India’s searing heatwave

New Delhi (CNN) — Nights are getting uncomfortably and dangerously hotter in India’s capital as people in the world’s most populous nation feel little respite from unrelenting temperatures. Nights are getting uncomfortably and dangerously hotter in India’s capital as people in the world’s most populous nation feel little respite from unrelenting temperatures. Northern India has endured a scorching summer — with one part of the capital of Delhi reaching the city’s highest temperature on record, 49.9 degrees Celsius (121.8 degrees Fahrenheit) earlier this month. 0:21 / 1:00 WRAL News Brief Watch More But the stifling heat persists even after the blazing sun has set. The city is cooling down by only 8.5 degrees Celsius at night compared to a 12.2 degrees cooling down in urban outskirt areas, a report published by the Centre for Science and Environment (CSE) last month tracking urban heat stress in Delhi has found. The warmer nights deprive people of rest and recovery from long hours of exposure to oppressive heat, particularly for people without access to air conditioning. Bicycle rickshaw driver Sagar Mandal told CNN that he’s been getting fewer passengers because people opt for air-conditioned taxis over open-air transport. “My body can’t take it, but I have to keep cycling. We are used to physical labor, we aren’t complaining about that. But this heat is not normal, something has to change,” the 39-year-old, who pedals people around the city, said. “No one cares if we live or die, no matter who you vote for this is a problem no one can solve,” he said. Nikhil Kumar, an auto-rickshaw driver said his workdays are getting longer and tougher amid the heat.

‘My body can’t take it’: Brutal nighttime temperatures give Delhi residents little respite from India’s searing heatwave

New Delhi (CNN) — Nights are getting uncomfortably and dangerously hotter in India’s capital as people in the world’s most populous nation feel little respite from unrelenting temperatures. Northern India has endured a scorching summer, with one part of Delhi reached 49.9 degrees Celsius (121.8 degrees Fahrenheit) in late May — the capital’s highest temperature on record. But the stifling heat persists even after the blazing sun has set. The city is cooling down by only 8.5 degrees Celsius at night compared to a 12.2 degrees cooling down in urban outskirt areas, a report published by the Centre for Science and Environment (CSE) last month tracking urban heat stress in Delhi has found. The warmer nights deprive people of rest and recovery from long hours of exposure to oppressive heat, particularly for people without access to air conditioning. Bicycle rickshaw driver Sagar Mandal told CNN that he’s been getting fewer passengers because people opt for air-conditioned taxis over open-air transport. “My body can’t take it, but I have to keep cycling. We are used to physical labor, we aren’t complaining about that. But this heat is not normal, something has to change,” the 39-year-old, who pedals people around the city, said. “No one cares if we live or die, no matter who you vote for this is a problem no one can solve,” he said. Nikhil Kumar, an auto-rickshaw driver said his workdays are getting longer and tougher amid the heat. “It doesn’t get any better at night, even at night I’m sweating, it rained a little last night but look how hot it is today, there’s no relief,” the 26-year-old driver said. Hotter nights are a consequence of the climate crisis, scientists have warned, heightening the health hazards of heat stress. Studies have shown higher nighttime temperatures make it harder to fall asleep and reduce deep wave and REM (rapid eye movement), both critical to how well the body repairs and refreshes itself at night. In the United States, for example, nights are warming faster than days in most of country, the 2018 National Climate Assessment found. Mandal, the cycle-rickshaw driver said he has been sleeping on the roof of his home for some hope of cooler air but only for a couple of hours.

‘My body can’t take it’: Brutal nighttime temperatures give Delhi residents little respite from India’s searing heatwave

New Delhi (CNN) — Nights are getting uncomfortably and dangerously hotter in India’s capital as people in the world’s most populous nation feel little respite from unrelenting temperatures. Northern India has endured a scorching summer, with one part of Delhi reached 49.9 degrees Celsius (121.8 degrees Fahrenheit) in late May — the capital’s highest temperature on record. But the stifling heat persists even after the blazing sun has set. The city is cooling down by only 8.5 degrees Celsius at night compared to a 12.2 degrees cooling down in urban outskirt areas, a report published by the Centre for Science and Environment (CSE) last month tracking urban heat stress in Delhi has found.

‘My body can’t take it’: Brutal nighttime temperatures give Delhi residents little respite from India’s searing heatwave

New Delhi (CNN) — Nights are getting uncomfortably and dangerously hotter in India’s capital as people in the world’s most populous nation feel little respite from unrelenting temperatures. Northern India has endured a scorching summer, with one part of Delhi reached 49.9 degrees Celsius (121.8 degrees Fahrenheit) in late May — the capital’s highest temperature on record. But the stifling heat persists even after the blazing sun has set. The city is cooling down by only 8.5 degrees Celsius at night compared to a 12.2 degrees cooling down in urban outskirt areas, a report published by the Centre for Science and Environment (CSE) last month tracking urban heat stress in Delhi has found. The warmer nights deprive people of rest and recovery from long hours of exposure to oppressive heat, particularly for people without access to air conditioning. Bicycle rickshaw driver Sagar Mandal told CNN that he’s been getting fewer passengers because people opt for air-conditioned taxis over open-air transport. “My body can’t take it, but I have to keep cycling. We are used to physical labor, we aren’t complaining about that. But this heat is not normal, something has to change,” the 39-year-old, who pedals people around the city, said. “No one cares if we live or die, no matter who you vote for this is a problem no one can solve,” he said. Nikhil Kumar, an auto-rickshaw driver said his workdays are getting longer and tougher amid the heat. “It doesn’t get any better at night, even at night I’m sweating, it rained a little last night but look how hot it is today, there’s no relief,” the 26-year-old driver said. Hotter nights are a consequence of the climate crisis, scientists have warned, heightening the health hazards of heat stress. Studies have shown higher nighttime temperatures make it harder to fall asleep and reduce deep wave and REM (rapid eye movement), both critical to how well the body repairs and refreshes itself at night. In the United States, for example, nights are warming faster than days in most of country, the 2018 National Climate Assessment found. Mandal, the cycle-rickshaw driver said he has been sleeping on the roof of his home for some hope of cooler air but only for a couple of hours. “I barely sleep these days,” he said. Exposure to heat waves during pregnancy may be associated with adverse outcomes such as preterm birth, according to a 2019 study. Older adults may have higher heart rates and more physiological stress when sleeping in warmer temperatures. A 2008 Australian study even found deaths due to mental and behavioral disorders rose during heat waves, especially for older adults.