Both have rapidly growing economies and are modernizing quickly. While China has the early lead, some believe that India will eventually overtake them because democracies have a superiority track record of maintaining societal stability.
I am putting my money on China based on this statistic from The Economist:
India's top computer scientists are feted around the world, yet most children in rural areas lack the basic education needed to find more productive work. Around half of all Indian women are illiterate, compared with a ratio of around one in seven in China.Democracy, shemocracy, if you can't educate your girls, what is the point? An educated populace is key to economic and world power in the 21st century, and with a female illiteracy rate that high, there is no way that India will be in the same ballpark as China.
I would also argue that sentencing 250 million women to a lifetime of illiteracy makes India a worse human rights violator than China. According to UN's Declaration of Human Rights elementary education is considered a human right and I would interpret that to include literacy.
If I had to choose between being illiterate or losing an arm, I would choose the arm without a second thought. Imagine the outrage if 1/2 of all Indian women were missing an arm. And yet what is happening now is even worse.
There is no way India is going to overtake China until they get serious about female education and literacy.
Update: Looks like at least one person is taking this seriously as Victor Lyons is on a mission to make one million rural Indian women literate over five years.