Residents in the southern Indian city of Bangalore have been waking up to a surreal sight: a lake covered in what appears to be billowing drifts of snow.

The frothy drifts cover vast stretches of Bellandur Lake, a 900-acre body of water near the country’s sprawling tech capital — and for a city with May temps hovering around 86 degrees Fahrenheit (30 C), it’s unlikely to be caused by a freak summer snowfall.

Bellandur Lake is no stranger to the surreal. The lake has been foaming up since at least 2015. And earlier this year, it took a turn for the biblical when it caught fire. The flames reportedly raged for some 30 hours, filling the air with ash and fueling appropriately apocalyptic musings among residents.

"Why in the world would a lake catch fire?" resident Sahni told National Geographic. "Water should be used to extinguish, not be fuel for a fire."

But the devil isn’t rising up from Bangalore’s lake. The culprit is likely the devil we know all too well: pollution.

Bangalore’s emergence as an industrial titan, along with the accompanying population surge, may have taken a toll on the lake that residents say they were once able to drink from.

Nowadays, both industrial and human waste have whipped it into a toxic frenzy that not only occasionally catches fire, but also spawns foaming drifts of detergents and other chemicals.

Needless to say, the days of clean drinking water from Bellandur are long gone. The air near the lake is hard to breathe, an acrid blend of sewage and chemicals. Just touching the froth is said to cause skin irritation.

A cautionary tale

There are, however, a few hopeful signs.

Indian authorities have stepped up measures to curb illegal dumping, including installing surveillance cameras along the shoreline.

More importantly, residents are rallying for a new sewage treatment plant that could dramatically reduce human waste entering the lake. In addition, citizen groups focused on cleaning up Bellandur are gaining momentum.

But perhaps most importantly, Bendalur’s shocking transformation from life-giving waters to toxic sludge may serve as a powerful caution to other cities facing rampant development — especially when that development outstrips environmental safeguards.

"The fire in the lake was a first-of-its-kind event in India. But this is a warning for every other city in the world which is developing," Priyanka Jamwal, an environmental scientist, told National Geographic.