It's a swamp cooler. https://en.wikipedia.org/wiki/Evaporative_cooler#Direct_evaporative_cooling . It'll cool the air and raise the humidity. This is quite useful in hot, dry areas, less so in hot, humid New Delhi, because when the humidity is high, the human body's own sweat-based cooling gets worse. The comments on the BP page point out that it's being used to cool industrial exhaust, not cool a home - take a look at the big louvers behind it. And it uses electricity to pump the water.
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