Once known for its mild breeze tree-lined avenues, and cool evenings Bengaluru has now turned into a furnace. On World Environment Day 2025, the city that was once India’s “Garden City” now serves as a cautionary tale a metropolis brought to its knees by decades of unchecked growth, ecological neglect, and climate denial.
For sanitation workers like Nagalakshmi, the crisis isn’t theoretical. It’s seared into the skin. Each morning, she walks 6–7 kilometers sweeping streets under the relentless sun, without shade or a place to rest. “It is scorching hot,” she says. “If I feel unwell, there’s nowhere to sit. Even drinking water feels risky there are no toilets around.”
Nagalakshmi, like thousands of other workers, is paying the price for a transformation she never asked for a transformation that has stripped Bengaluru of its blue-green lifelines and replaced them with concrete, glass, and heat.
From Garden City to Urban Oven
Bengaluru was once celebrated for its moderate climate, thanks to its abundant trees and over 1,000 interconnected lakes. But over the last 50 years, the city has lost almost all of this ecological armor.
Since 1975, Bengaluru’s average air temperature has risen by 0.23°C every decade and nearly double that rate in the past 10 years. Once 19°C in the 1990s, temperatures today regularly touch 36–37°C, with parts of the city repeatedly crossing 41°C. What once kept the city temperate water bodies, forests, parks have been buried under glass towers and tar roads.
In 1973, green cover spanned 68% of the city. In 2025, it’s down to just 6%.
Urban planners point to a brutal fact: 85% of Bengaluru’s surface is now built-up and impervious. More than 79% of lakes have been encroached or erased. What used to be lakebeds are now bus terminals, parking lots, and shopping complexes. “Everything has turned into hard surfaces,” explains urban planner Anup Naik. “Even Bengaluru’s first bus stand was a lake once.”
The result is not just hotter days, but a drastically altered urban heat signature with some areas becoming long-term “heat stress zones,” where temperatures remain dangerously high year after year.
Workers in the Crossfire
The hardest hit are those least responsible for the crisis. Sanitation workers like Nagalakshmi and Hooliyamma spend their days outdoors, sweeping roads, collecting waste, and navigating heat zones without protection.
Workers’ unions have raised demands with the city municipal corporation, Bruhat Bengaluru Mahanagara Palike (BBMP), asking for shelters, rest zones, and better access to sanitation. But the response has been slow. Parks remain closed outside early morning hours. Cooling shelters are rare. And the city’s heat policy is still in its infancy.
A City Designed to Trap Heat
Experts say that urban design choices are aggravating the heat. Glass-façade high-rises reflect and trap solar radiation, pushing surrounding temperatures up by 2–3°C. Poor ventilation and heat-retaining surfaces create microclimates that make central zones unbearable, especially for low-income workers and pedestrians.
This is the urban heat island effect in action: cities becoming significantly hotter than surrounding rural areas because of dense construction, vehicular emissions, and vanishing greenery.
“Basic planning ideas like building orientation, natural cooling, and green buffers are missing,” says Mitashi Singh from the Centre for Science and Environment (CSE). “Even air conditioners add to the problem by venting hot air outdoors, creating a vicious cycle.”
Climate Tech at Work But for Whom?
While the poorest battle heatstroke on the streets, scientists at IISc’s ARTPARK are working on AI-powered tools to forecast heat risk at the sub-district level. These models promise 10-day forecasts, infrastructure mapping, and vulnerability tracking. The idea is to help local authorities prepare heat action plans and prioritize high-risk areas.
“AI can detect patterns humans miss,” says computational scientist Vybhav GR. “We can identify which taluks face the greatest heat risk and suggest targeted interventions like cooling centers and early warnings.”
But implementation remains the gap. For workers like Nagalakshmi, heat forecasts won’t help unless they translate into water points, shaded rest stops, and early leave protocols during high-risk days.
Patching a Broken Ecosystem
In response to legal and public pressure, BBMP has launched lake rejuvenation efforts. Officials say 183 of the city’s 202 lakes are still “live,” and projects are underway to desilt, de-encroach, and replant native species. But these efforts are uneven and slow.
Some lakes have been turned into gated recreational parks for elites, while others remain choked with sewage. Tree-planting drives often ignore native biodiversity or community access.
Ecologists warn that without restoring interconnected green-blue corridors lakes, wetlands, forest patches Bengaluru will continue to overheat. “Lakes reduce urban temperature by at least 2°C,” says IISc’s TV Ramachandra. “We must reclaim green commons and protect them as public cooling infrastructure.”
A City at Crossroads
Bengaluru’s heat crisis is not an isolated weather problem it is a full-blown urban planning emergency. It reflects how decades of decisions have sacrificed ecology for unchecked development. It lays bare a deeper injustice where the poorest labor under the worst impacts, with little relief in sight.
For Nagalakshmi, the city’s future doesn’t lie in high-tech forecasts or corporate green pledges. It lies in whether she gets a shaded corner to rest, a clean toilet nearby, and the dignity of working in humane conditions.
At day’s end, she returns home and lies flat on the bare floor the only spot that still holds a trace of coolness. That, for now, is her climate resilience.