Exit polls are predicting a significant win for Prime Minister Narendra Modi of India when final results are announced on Thursday. That’s not only good news for Mr. Modi; it’s also good news for his country.

While his bold economic policies generated a blizzard of controversy, I came away from a recent trip to India more optimistic about the prospects for India and its 1.3 billion people. For that, much credit goes to Mr. Modi. Elected in 2014 on a platform of aggressive change, he has delivered on important reforms to modernize India’s hidebound economy.

Perhaps the most important challenge that Mr. Modi had to address was lagging productivity. In part, that’s due to the country’s slowness to urbanize. Mumbai may be wildly overcrowded, but India’s overall urbanization rate is only 34 percent, compared with China’s 59 percent. And it’s also a consequence of poor infrastructure and the estimated 81 percent of Indians who work in the “informal” economy.

At first glance, some of Mr. Modi’s reforms may seem small. He replaced a portion of a complex tax system with a kind of national sales tax. The change is forcing businesses operating in the informal sector to regularize and — this is important — begin to pay taxes. (India’s taxes as a share of the size of the economy are among the lowest in the world.)