Bengaluru's Vanishing Lakes: A Slow Crisis Beneath a Booming City

Long before it was India's technology capital, Bengaluru was known by a quieter title: the City of a Thousand Lakes. Today, most of those lakes exist only in old maps and municipal records — and the ones that remain are fighting to survive.

A city built on water it made itself

Bengaluru sits on a plateau, far from any major river. For centuries, that meant the city couldn't rely on a natural water source the way most cities do. So its rulers — from the Kempegowda dynasty onward — built one instead: a vast, interconnected network of human-made tanks and lakes, known locally as keres, engineered to catch monsoon runoff and pass the overflow from one lake down to the next. It was a centuries-old, entirely gravity-fed water management system, and it worked well enough to sustain a growing city for generations.

From a thousand lakes to a few hundred

Historical surveys place the number of lakes and tanks in and around Bengaluru well into the hundreds, by some counts over a thousand, at the start of the 20th century. Today, credible estimates put the number of lakes that still hold water and function as lakes at a small fraction of that — commonly cited figures hover around 200, and many of those are in poor ecological health.

The drop isn't the result of one dramatic event. It's decades of incremental loss: lakes drained and built over as the city expanded outward, the stormwater channels (rajakaluves) that once connected one lake to the next encroached upon or blocked entirely, and dying lakes quietly reclassified as "dry land" and sold off.

When the channels connecting lakes disappear, the lakes don't just lose water — the city loses its ability to manage a flood.

What's left is often not clean

Survival hasn't meant health. Many of Bengaluru's remaining lakes receive a steady flow of untreated sewage and industrial effluent, a legacy of underground drainage infrastructure that never kept pace with the city's growth. Bellandur Lake, the city's largest, has become nationally known for exactly the wrong reasons — toxic white foam spilling onto nearby roads during heavy rain, and, on more than one occasion, patches of the lake's surface catching fire from the buildup of flammable industrial waste.

The consequences reach well beyond the lakes themselves. Groundwater tables have dropped as recharge zones vanished under concrete. Neighborhoods far from any lake now flood during the monsoon, because the natural overflow paths that used to carry excess water away no longer exist. Biodiversity that depended on these wetlands — migratory birds, fish, amphibians — has thinned out considerably.

Signs of a turnaround

The story isn't only decline. Citizen groups and neighborhood lake-user associations have taken on the unglamorous work of rejuvenating individual lakes — desilting, fencing off encroachment, replanting native vegetation along the banks, and pushing civic authorities to intercept sewage before it reaches the water. A number of restoration projects, some government-led and some community-driven, have brought individual lakes like Jakkur and Puttenahalli back to a genuinely healthy state, complete with returning birdlife. They're proof that the damage isn't irreversible — it just requires sustained, unglamorous work.

Why this matters to us

We work at the intersection of technology, sustainability, and enterprise — and Bengaluru's lakes are a reminder of what's at stake when growth outpaces stewardship. It's the same reason we took on the role of stewards and consultants for the Guinness World Records saplings initiative with the Bengaluru Development Authority: real environmental impact happens through sustained, on-the-ground work, not one-off gestures.