New Delhi, Oct. 13 -- Businesses in India have typically treated water as a steady input-not perfect, but reliable enough. Climate change is unravelling that assumption. Variable rainfall, falling groundwater tables, depleting aquifers and intensifying floods are reshaping how firms source this most basic of industrial inputs. Water has quietly become a new frontier of business risk.

Rising temperatures, erratic monsoons, frequent droughts and increasingly likely extreme weather events are reducing reliable water availability while driving up demand, especially from water-intensive industries like power generation, textiles and steel. By 2030, for instance, 70% of India's thermal power plants are projected to face severe water stress, th...