How Traditional Terracotta Coolers Beat the Unprecedented Heat in India

In India's scorching summer heat, the ancient practice of chilling water in terracotta pots is inspiring new trends – from cooling towers to screens for buildings.

For centuries, terracotta "matka" pots have helped keep water cool (Credit: Getty Images)

Nandita Iyer hates chilled water. And yet, when temperatures soared in India this May, with even her home-city of Bengaluru hitting a record high, the cookbook author and food blogger knew she had to do something to stay hydrated. And so she turned to a favourite childhood fixture: the matka – a terracotta pot composed of two different types of clay and designed to act as domestic water cooler in the home.    

"I have sensitive teeth, so drinking refrigerated water feels like a shock to my system; the matka keeps water just cool enough that it's comforting to sip on," she says, recalling how a wet muslin cloth on top of the pot helped lower the water temperature further still. "I remembered how nice this naturally chilled water would feel in the hot Mumbai summers growing up, so when Bengaluru weather started behaving like Mumbai, I decided to get a similar pot."

The matka has ancient roots. When water fills a terracotta pot, it sinks into every pore and crevice. As the water trapped inside these pores evaporates, the process slowly draws out the latent heat from the water within. The pot cools down after losing its heat to evaporation and so the remaining water inside it cools down too. For centuries, therefore, India's rural areas have turned to earthen pots for their cooling needs – with the earliest known records dating back to the Harappan civilisation, more than 3,000 years ago.

Continue reading