Bengaluru's Tech Corridor Keeps Flooding Because the City Paved Over Its Own Drains

In September 2022, a single evening of heavy rain turned stretches of Bengaluru's Outer Ring Road tech corridor into a waist-deep waterway. Images of employees being ferried into office parks by tractor and boat went viral within hours — India's software capital, underwater. It wasn't a freak event. It was the same story the city has been telling itself for years, just louder that time.

The drains that used to be the point

Bengaluru's stormwater drains — locally called rajakaluves — were never an afterthought. They were the plumbing for the city's famous chain of interconnected lakes, engineered centuries ago to catch monsoon runoff and route the overflow from one tank to the next downstream. We've written before about how that lake network has shrunk from the thousands to a few hundred (see Bengaluru's Vanishing Lakes). The rajakaluves are the other half of that same story: when the drains that feed and connect the lakes get built over, both the lakes and the drainage they depend on stop working.

Where the water is supposed to go — and where it can't

On paper, primary rajakaluves carry a mandated no-construction buffer to leave room for monsoon flow and maintenance access. In practice, years of unauthorized construction, layouts approved without checking drain alignments, and encroachment by both informal structures and large developments have narrowed or completely buried stretches of the network, particularly along the fast-growing IT corridor around Bellandur, Sarjapur, and Marathahalli. A drain designed to carry a certain volume of water simply cannot, once a chunk of its width is buildings instead of channel — the water still has to go somewhere, and increasingly that's the nearest road or office park.

Growth that outran its own plumbing

The irony is that the areas that flood hardest are the ones that grew fastest. Bengaluru's IT corridor was built at a pace few cities have matched, largely on land that used to be farmland, wetland, or lakebed with its own natural drainage path. Roads, parking lots, and office campuses replaced absorbent ground with hard surfaces that shed rainwater instantly instead of letting it soak in — pushing more water, faster, into a drain network that was already losing capacity to encroachment on the other side.

A city can add office towers faster than it can add drains. Bengaluru has spent two decades proving it.

The response so far

The flooding has drawn real institutional attention: the National Green Tribunal has taken up Bengaluru drain and lake encroachment cases over the years, BBMP has run drives to demolish structures built on rajakaluve land, and the state has periodically promised a comprehensive stormwater drain master plan for the city. Enforcement has been the hard part — reclaiming a buried drain usually means demolishing something that's already built and often already occupied, which makes every case slower and more contested than approving the original encroachment ever was.

The same broken plumbing, both ways

It's worth sitting with the contradiction here: this is the same city that runs dry every summer, trucking in tanker water to neighborhoods whose borewells have failed (see why Bengaluru runs out of water every summer). A functioning rajakaluve network doesn't just prevent floods — it's also meant to recharge the same groundwater and lakes the city is short of every April. Bengaluru isn't short on rain over a year. It's short on infrastructure that can hold onto water when it arrives and get rid of it safely when there's too much at once.

Why this matters to us

This is exactly the kind of infrastructure gap our venture Ecoverse is built to work alongside — its initiatives already include water body rejuvenation and urban micro-forests, both of which do double duty as flood buffers: a restored lake or a patch of permeable green space can hold water a paved surface never will. Fixing a city's drains is a government-scale project. Restoring even one lake or one green pocket at a time is something a community can actually own.