But his role as on-air talker combines two of his greatest strengths. The first is his deep understanding of India’s grass roots, developed over decades as a foot soldier and evangelist of the Hindu right. The other is his populist mastery of storytelling for a digital media sphere where he can effectively communicate his government’s popular programs, from free rations to improved infrastructure, and make virtually any message go viral.

“On top of the system is Modi, whose communication is very carefully thought out, almost always positive, and always framed to present the indistinguishability of Modi from India,” said Joyojeet Pal, who studies political use of social media at the University of Michigan.

Each broadcast of “Mann Ki Baat,” which loosely translates as Conversations From the Heart, is scripted for a nation on the ascent, connecting the local with the national and the global. All the while, the program associates Mr. Modi with every positive happening, big or small, and every solution, tangible or spiritual.

On occasion, he talks about international events where India commands the spotlight, but he most often addresses issues of basic government services, down to the tiniest details. Mr. Modi puts himself at the center of conversation over the delivery of some of life’s most rudimentary amenities, like piped water or toilets. From his more partisan pulpits, he blames India’s previous elite for denying the masses these necessities.

Water scarcity is a frequent subject. “As a responsible citizen and as a member of society, we will have to cultivate the habit of conserving every drop of water,” Mr. Modi said in one episode, before giving the example of a coastal village that has a “200-year-old underground water tank,” recharged with rainfall.

Another regular topic is pressures on young people, including exam stress in a country — this part is left unsaid — where students find too few job opportunities after graduating from a competitive education system.