India is now the world’s third largest economy in terms of Purchasing Power Parity [PPP], moving ahead of Japan. This, according to a World Bank Report that is based on the bank’s 2011 International Comparison Program (ICP).
The same report shows that Mexico’s economy is now ahead of Canada and China is close on USA’s heels. Given that the figures are based on the 2011 numbers, chances are, as of now in 2014, China could well be ahead.

”The United States remained the world’s largest economy, but it was closely followed by China when measured using PPPs. India was the world’s third largest economy, moving ahead of Japan,” the report noted. “Because economies estimate their GDP at national price levels and in national currencies, those GDPs are not comparable. To be compared, they must be valued at a common price level and expressed in a common currency,” the report explains, outlining the justification for a PPP-based comparative look at world GDPs.
To know more click on the following stories in India’s Economic Times:
For the World Bank’s summary read: http://www.worldbank.org/en/news/press-release/2014/04/29/2011-international-comparison-program-results-compare-real-size-world-economies