On some mornings, across India’s reef-rich waters, the sea lies like a sheet of glass from the Andaman and Nicobar Islands and Lakshadweep to the long coasts of Goa, Kochi, and Puducherry, and beyond. Shifting between blue and green, coral gardens bloom quietly beneath, their edges catching the light. It is here, and during the recently-concluded Professional Association of Diving Instructors’ (PADI) Go Eco Month in April — a global campaign that turns everyday diving into acts of conservation — that the illusion of untouched waters was both encountered and undone.

From above, the waters look pristine but under, the eye begins to adjust. A flash of colour gives way to a torn plastic bag snagged behind a coral head, a length of fishing line drifting where fish once moved freely. For those who have been under, who have watched corals breathe and bleach and traced the slow spread of debris across the ocean floor, the illusion does not last long.