New Delhi, March 5 -- Reusing treated water has long been a part of traditional practices, with past generations using it for horticulture and daily needs. However, rising populations have driven water demand and wastewater generation to unprecedented levels.

India generates over 72,000 megalitres per day (MLD) of sewage, but only 28 per cent is treated and even less is reused. Untreated wastewater continues to pollute rivers, lakes and groundwater, exacerbating the water crisis. With just 4 per cent of the world's freshwater, India sustains 18 per cent of the global population. By 2030, water demand is set to double and per capita availability may drop below 1,200 cubic metres by 2050.

Cities like Delhi, Bengaluru and Chennai already f...