(Bloomberg Businessweek) -- T-Series, which owns the rights to about 70% of the Bollywood songbook recorded in the past three decades, has been flooding YouTube with music videos. Its ascent to the top of the site—it dethroned comedian-gamer-troll PewDiePie—was powered by an explosion of cheap mobile data in India, which has helped bring online about 300 million new users since 2016.