India will become world largest economy - 2050

According to a report given by Citigroup, Inc. (NYSE:C),  

China is forecast to become and to overtake the U.S. as the world’s largest economy in 2020.
India is expecting to become second largest economy in the world by overtake the U.S in 2040.

And India will take the crown of world's largest economy in the world in 2050.

In 2011,

1.USA

2.CHINA

3.JAPAN

4.INDIA

In 2015,

1.USA

2.CHINA

3.INDIA

4.JAPAN

In 2020,

1.CHINA

2.USA

3.INDIA

4.JAPAN

In 2040,

1.CHINA

2.INDIA

3.USA

4.JAPAN

In 2050,

1.INDIA.

2.CHINA

3.USA