Special roof design cools shanty by up to 13 degrees says NGO study

New Delhi, May 6 (PTI) As heatwaves intensify across India, disproportionately impacting the urban poor, an environmental group trialled various measures to combat heat stress in informal settlements across the national capital and managed to reduce temperatures by up to 13 degrees Celsius with one of them.
    These measures include heat-resilient roofing systems made from locally available recycled materials and a community-based weather monitoring system, both aimed at building resilience and protecting vulnerable communities from rising temperatures.
    Chintan Environmental Research and Action Group has put its findings in its report and highlighted the urgent need for gender-responsive, community-led interventions to build heat resilience in India's informal settlements.
    In the pilot projects, various cool roof models using locally available materials such as jute, bamboo and recycled PET bottles were tested. One roof design, which combined tin, insulation sheets and jute, was able to reduce temperatures by up to 13 degrees Celsius compared to unmodified roofs, according to the report released on Tuesday.
    Emphasising the importance of integrating nature-based solutions like green spaces and water bodies into urban planning, the report underscored the need to implement policies to cool housing, especially in slums, through the installation of cool roofs and thermal insulation.
    The recommendations by the Chintan group are based on a pilot project conducted in five informal settlements in Delhi between 2022 and 2024, where various cool roof models and community-based interventions were tested.
    The report identifies the lack of heat-resilient infrastructure as a key vulnerability. To address this, it suggests embedding cool roofing standards into government housing schemes such as the Pradhan Mantri Awas Yojana-Urban (PMAY-U). Furthermore, the report stresses the importance of incorporating flexible budget provisions to maintain and repair heat-mitigation infrastructure over time.
    Chintan group founder Bharati Chaturvedi told PTI that the cost of installing heat-resilient roofs in informal settlements is estimated at around ₹4,000 to ₹5,000 per house.
    However, the cost is expected to decrease with large-scale implementation. As part of the pilot project, the group tested the intervention on 600 white roofs covering 1,000 houses, Chaturvedi said.
    One major recommendation is to create fiscal incentives for low-income families to implement heat-resilient housing strategies. The report also proposes the establishment of green jobs and community weather monitoring systems, particularly through CSR funding, to aid vulnerable populations in adapting to extreme heat.
    The findings in the report are further supported by data indicating the serious economic and labour impacts of rising temperatures.
    In 2022, a study by Duke University said that between 2001 and 2020, India lost 259 billion labour hours annually due to heat and humidity, resulting in an economic loss of approximately Rs 46 lakh crore.
    Projections indicate that by 2030, nearly 5.8% of total labour hours could be lost, said a report released by the United Nations Economic and Social Commission for Asia and the Pacific (UNESCAP) in 2024.
    The informal sector, where 90 per cent of India’s workforce is employed in physically demanding jobs, stands to bear the brunt of these heat-related losses.
    Raising the issue of heat poverty, the report mentions families in slums who take out high-interest loans to buy air conditioners, only to find them impractical due to electricity instability. "In many informal settlements, the electricity supply is unreliable, making traditional cooling devices an unfeasible solution for many," the report read.
    The report’s proposed solutions particularly centre around community involvement. “Chintan trained over 1,000 women waste-pickers, who not only helped map heat hotspots but also operated weather stations to provide real-time heat alerts using WhatsApp. These women were instrumental in raising awareness of heat risks and engaging local residents in heat mitigation efforts,” the report read.
    However, the report also talks about the maintenance challenges, as some roofs deteriorated quickly, especially those painted with white cool coatings, highlighting the importance of durable solutions that can withstand the extreme heat conditions of India’s informal settlements.
    The 2024 Lancet Countdown report on health and climate change flagged alarming trends for India, including a sharp rise in heat-related deaths and economic losses linked to climate impacts. The report noted a 167 per cent increase in heat-related mortality among people over the age of 65 since the 1990s.
    In addition, India witnessed an estimated loss of 181 billion labour hours in 2023 due to heat exposure, underscoring the growing risks posed by rising temperatures to both health and productivity.
    Overall, the report by the Chintan group stresses that heat action plans must go beyond infrastructure and include systemic, community-driven responses to build resilience against rising temperatures. The findings suggest that unless there is a shift in policy to prioritise heat adaptation in urban slums, the consequences for India’s vulnerable populations, especially in the informal sector, will be dire.
    About 42 per cent of India’s land area is reeling under drought conditions, with 6 per cent classified as exceptionally dry — nearly four times the spatial extent recorded in the same period last year — according to the 2019 data from the Drought Early Warning System (DEWS), a real-time drought monitoring platform.
    Andhra Pradesh, Bihar, Gujarat, Jharkhand, Karnataka, Maharashtra, parts of the Northeast, Rajasthan, Tamil Nadu and Telangana have been among the worst affected. These states account for nearly 500 million, representing nearly 40 per cent of the country’s total population.

(This story has not been edited by THE WEEK and is auto-generated from PTI)