TIRUNELVELI, India – Just after dusk on a warm mid-January evening, attorney DA Prabakar greeted several visitors on the dimly lit street in front of his home here in southern India. The air was desert-dry and dusty in this rain-scarce river city.

CHENNAI, India – T. Rajan tried all manner of entrepreneurial enterprises. He sold scrap paper and cardboard to recyclers. He built a street corner chai and cigarette cart, and repaired truck and bus tires. He started an office cleaning service for high-tech companies in the growing IT sector south of the city center. None of these delivered the financial returns and workday flexibility of selling clear, sky blue, 20-liter water “cans” in Chennai’s immense bottled water industry.

Before the 2015 floods that drowned Chennai, Pradeep John spent several years posting thorough and dutifully accurate updates and alerts on Twitter and Facebook as the Tamil Nadu Weatherman. An amateur meteorologist who developed considerable expertise in weather data and satellite imagery, John’s online followers relied on his crisp forecasts and advice.

CHENNAI, India – Almost a decade ago, when the first of Chennai’s bleach-white IT office buildings replaced coconut groves along the Bay of Bengal south of the city center, leaders hailed the potential for a new wave of clean jobs. Nine years later, it is clear that planners did not fully anticipate the consequences.

VENGANTHANKUSI, India – Vijayakumar, 51, was a successful rice grower his entire life until this rainless harvest season. Described by family and friends as a tall, steady man of few words, Vijayakumar seemed unbent by the paralyzing consequences of Tamil Nadu’s deepest drought in 140 years.

VILAMBUR, India – The mammoth coal-fired Cheyyur electrical station was first imagined by bankers at India’s Power Finance Corporation and senior engineers across town at the Central Electric Authority. That was in 2005, when the country was rich in fossil fuel resources and desperate for electric power. Though India mined more coal than almost any other country, endemic blackouts and brownouts enfeebled its economic prospects.

TUTICORIN, India – Among the 75 government agencies that manage and regulate this bewitching and often impassioned nation, there is no Ministry of the Future. There should be.

Over the course of 1,800 miles, 5,300 vertical feet, and at least five name changes, the Brahmaputra River, in sometimes turbulent outbursts, flows from the Tibetan plateau to the Bay of Bengal. Along the way, it crosses three countries, including major geopolitical rivals China and India, and supplies 90 percent of downstream Bangladesh’s freshwater during the dry season.