Obama most powerful; Sonia, Manmohan in top 20: Forbes

Prime Minister Manmohan Singh and Congress President Sonia Gandhi have been named among the top 20 most powerful persons in the world by Forbes magazine in its annual power rankings which placed US President Barack Obama as number one for a second year in a row.

India's richest businessman Reliance Industries chairman Mukesh Ambani and and Arcelor Mittal CEO Lakshmi Mittal also feature in the list that comprises 71 mighty heads of state, CEOs, entrepreneurs and philanthropists who "truly run and shape the world of 7.1 billion people."

Gandhi dropped a notch from last year's list and ranks at number 12 this year ahead of Chinese Vice Premier Li Keqiang and French President Francois Hollande. Forbes said the 65-year-old leader of India's ruling political party has the reins of the world's second-most-populous country and tenth-largest economy.

"Son Rahul is next in line to take over India's most famous political dynasty," it added. Coming in at the 20th spot is Singh, the Oxford and Cambridge-educated economist who is the architect of India's economic reforms. Singh had ranked 19th in the list last year.

"But Singh's quiet intellectualism is increasingly seen as timid and soft," Forbes added. Ambani, owner of the world's most expensive private residence, ranks 37th in the list. Forbes said the petrochemical billionaire is India's richest and Reliance Industries is the nation's most valuable company. It however described Ambani's support for disgraced former Goldman Sachs Director Rajat Gupta as a "low point" for him in 2012.