New Delhi, Jan. 26 -- When Harvard Professor Gita Gopinath told a Davos audience that pollution costs India more dearly than tariffs, she wasn't being provocative. She was making a strictly economic point: pollution is a continuous tax on productivity, public finances and human capital-unlike tariffs, which are episodic and negotiable. Hence tackling pollution "on a war footing" should be a top national mission.

Days earlier, Indore-celebrated as India's 'cleanest city' year after year-was forced into a humiliating reckoning. At least eight people died after allegedly drinking contaminated water in one locality, while hundreds were hospitalized.

The cause may have been a local civic failure: an ageing pipeline network, poor safeguards a...