India at a crossroads: reduce the risks of economic concentration.

India is poised to become the world's most important country in the medium term. It has the largest population (which is still growing), and with a per capita GDP that is just one-quarter that of China's, its economy has enormous scope for productivity gains. Moreover, India's military and geopolitical importance will only grow, and it is a vibrant democracy whose cultural diversity will generate soft power to rival the US and the UK.

One must credit Prime Minister Narendra Modi for implementing policies that have modernized India and supported its growth. Specifically, Modi has made massive investments in the...