Mumbai Faces Rising Heat Crisis Amid Shrinking Green Cover And Urban Overbuild, Experts Warn

Mumbai is heating up—literally and rapidly. A combination of unchecked urban development, shrinking green spaces, and outdated construction practices is driving record-breaking temperatures across India’s financial capital, experts warn. Environmentalists, scientists, and industry leaders are now calling for urgent, integrated climate action to safeguard the city’s future.

Swati Herkal, an environmental socialist and member of the Rotary Club of Wai, Maharashtra, highlighted the long-term warming trend with alarming data. “A 2021 multi-university study found that from 1991 to 2018, Mumbai’s average temperatures rose by 2.2°C. During the same period, the city’s built-up area increased by 66%, intensifying the urban heat island effect,” she said.

The city’s hottest February day in five years was recorded just months ago in February 2025, with temperatures hitting 38.7°C and prompting a rare heatwave alert from the India Meteorological Department. This trend follows other extreme weather events, including the deadly nationwide heatwave of 2015, when Mumbai also experienced abnormally high temperatures.

"It's Not Just The Heat — It's The Humidity"

According to Priyanka Bhide, Co-Founder of the Kubernein Initiative, what makes Mumbai’s climate particularly challenging isn’t just the rising temperatures—it’s the oppressive humidity. “Mumbai has always been a humid city, but now it’s not just humid—it’s humid and unbearably hot,” Bhide said. “The combination is dangerous. The city is seeing higher average temperatures every year, and the sticky heat is lasting longer into months that were previously considered ‘cooler’.”

She also noted that the city's climate resilience infrastructure hasn’t kept pace with these shifts. “We’re living through what feels like extended summers. Earlier, the humidity was something Mumbaikars were used to managing. Now, it’s accompanied by heat that pushes the limits of physical endurance, especially for those without access to cooling,” she added.

Bhide stressed that the urban poor and informal settlements face the worst consequences. “Humidity combined with rising temperatures amplifies health risks. It’s no longer just uncomfortable—it’s a public health issue.”

Vanishing Green Spaces, Vertical Expansion

Herkal emphasized that vanishing tree cover is worsening the crisis. “Trees do more than beautify—they cool urban areas, filter air, and reduce surface temperatures. As Mumbai replaces green spaces with concrete, especially in low-income neighborhoods, the most vulnerable residents suffer the most,” she said.

Vertical urban expansion, another hallmark of Mumbai’s growth, is contributing to trapped heat and poor ventilation. “High-rises respond to density but often ignore ecology. Without green planning, vertical growth turns cities into pressure cookers,” Herkal warned.

While the Brihanmumbai Municipal Corporation (BMC) and the Maharashtra government have introduced initiatives such as cool roofs, urban forestation, and tree plantation drives, Herkal argues these are only first steps. “We need a city-wide, climate-resilient master plan that integrates heat mitigation into every phase of urban planning.”

The Density Dilemma

Dr. Eilia Jafar, a humanitarian and development expert, pointed to the role of population density in amplifying heat stress. “Areas like Dharavi, Kurla, and Chembur are densely packed, with little ventilation and sparse greenery. Informal housing with tin or asbestos roofs becomes unbearably hot, severely impacting health—especially for children and the elderly,” she explained.

Jafar added that Mumbai is experiencing a rising number of extreme heat days—temperatures exceeding 38–40°C. “Between 1973 and 2020, Mumbai recorded 10 heatwaves and 2 extreme events. April 2024 reached 39.7°C, the hottest in 15 years. Projections suggest by 2040, 60% of the year could consist of high-heat days. By the 2080s, average temperatures could rise by 2.5–4.5°C,” she said.

Marine Ecosystems Under Stress

Rising sea surface temperatures are also endangering Mumbai’s marine biodiversity. “We’re seeing coral bleaching, oxygen depletion, and declining fish stocks,” said Jafar. “Industrial pollution and land-based runoff are damaging marine ecosystems, threatening coastal livelihoods and food security.”

Building Smarter, Cooler Cities

Aaditya Sharda, Co-Founder of Infra.Market, believes the solution lies in transforming how we build. “Traditional construction traps heat and consumes more energy. Instead, we should use thermally efficient concrete, low-carbon cement, and AAC blocks—which are lightweight, insulating, and more sustainable,” he said.

Sharda added that sustainable practices must go beyond materials. “We need to embed water reuse, minimize waste, and recycle industrial byproducts like fly ash. At Infra.Market, we’ve seen how sustainable construction can both reduce emissions and improve livability.”

A Path Forward

Experts agree that Mumbai must look to global models. Cities like Singapore and Barcelona are leading with green corridors, climate-sensitive building codes, and community-first urban planning. Herkal stressed that such frameworks are adaptable. “Mumbai can—and must—create a sustainable blueprint. The time to act is now.”

As Mumbai braces for another sweltering summer, the growing consensus is clear: incremental fixes aren’t enough. Only a bold, integrated approach to urban resilience can prevent the city from becoming unlivable in the decades.