India, Feb. 26 -- R Nallakannu's politics began with rivers. Long before environmentalism became a language of policy or climate summits, he understood something simple and elemental. When a river is wounded, the poor bleed first. Through decades of political life, he returned again and again to that truth, standing firmly against sand mining, resource plunder and projects that threatened fragile landscapes. With his passing at 101, Tamil Nadu loses not only a veteran communist leader but one of the last public figures who saw ecology as a moral question.

To many, he looked like a man from another century. White shirt, worn sandals, a walking stick, and a quiet presence that never demanded attention. Yet his gentleness hid a fierce resol...