Indra Nooyi, world's 4th most powerful woman

Chief Executive-designate of PepsiCo Indra Nooyi, Congress President Sonia Gandhi, and ICICI Bank's Lalita Gupte and Kalpana Morparia are among the 100 most powerful women in the world.

India-born Nooyi finds herself as the fourth most powerful woman on earth, while Sonia Gandhi occupies the 13th position on the list.

Joint managing directors of of ICICI Bank Gupte and Morparia are on the 93rd position, while Vidya Chhabria, chairperson of Jumbo Group, Dubai, is at the 95th spot.

Angela Merkel, the first woman to become chancellor of Germany, has displaced Condoleezza Rice as No. 1 on our list of the 100 Most Powerful Women.

Merkel won a tight election last year to unseat Gerhard Schröder as chancellor. She's a former physicist from East Germany and a firm believer in free-market capitalism. Since taking office, Merkel has won respect on the world stage and popular appeal in Germany for her quiet diplomacy.

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Despite her short time in office, Merkel has been dazzling world leaders, including Tony Blair and George W. Bush. But Merkel has a tough fight ahead of her. Her approval ratings have declined to 56 per cent from 80 per cent earlier this year, making it more difficult for Merkel to win big with key legislative initiatives, including health care reform and corporate tax restructuring.

She inherited a stagnant economy that has only lately shown signs of revival. At the same time, Merkel also has allied Germany with the U.S. to oppose Iran's nuclear activities, and she was vocal on energy security at the G8 summit meeting this summer, where she was the only female leader at the table.

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Behind the scenes, Merkel has been making a big push to ramp up U.S. investment in Germany. In May and in June, Merkel traveled to the US without fanfare (declining media interviews), to meet in closed-door sessions with US industry leaders, from Coca-Cola chief Neville Isdell to General Electric's Jeffrey Immelt to Henry Paulson, then the chair of Goldman Sachs Group.

And Merkel is hardly the only woman making waves on the international stage. There are just 53 Americans on our list of the World's 100 Most Powerful Women, attesting to the growing power of women worldwide. More women than ever before are running entire countries, not just companies and foundations.

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This year's list includes 30 women in the top echelons of government, up from 24 in last year's ranking. In the past 12 months Ellen Johnson-Sirleaf became president of Liberia, Michelle Bachelet president of Chile and Han Myung-sook South Korea's first female prime minister.

Women are also flexing their muscle in other ways. Neelie Kroes, the European commissioner for competition, recently made headlines for slapping around software giant Microsoft (fine: $358 million). Meanwhile, Melinda Gates is overseeing a $30 billion donation from Warren Buffett to the Bill & Melinda Gates Foundation.

The New York nonprofit research organization Catalyst has found that the number of high-ranking female officers remained essentially flat over the last three years in the biggest US companies. But we found 48 women running big companies as chief executives or chairwomen throughout the world, up from 35 last year.

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Since last year's list, Indra Nooyi, Irene Rosenfeld and Patricia Woertz were named to the top jobs at PepsiCo, Kraft Foods and Archer Daniels Midland.

Our power rankings are based on a composite of visibility (measured by press citations) and economic impact. The latter, in turn, reflects three things: résumé (a prime minister is more powerful than a senator); the size of the economic sphere over which a leader holds sway; and a multiplier that aims to make different financial yardsticks comparable. For example, a politician is assigned a gross domestic product number but gets a low multiplier, while a foundation executive is assigned the foundation's assets but gets a high multiplier.

The World's Most Powerful Women was edited by Elizabeth MacDonald and Chana R. Schoenberger.

The package was reported by Megha Bahree, Erika Brown, Helen Coster, Suzanne Hoppough and Tatiana Serafin. Additional reporting by Victoria Murphy Barret, Heidi Brown, Stephane Fitch, Jack Gage, Susan Kitchens, Luisa Kroll, Claire Miller, Anne P. Mintz, Zina Moukheiber and Cristina von Zeppelin.

With assistance from Catalyst, a research group; Laura Liswood, secretary general of the Council of Women World Leaders; and Marie Wilson, head of the White House Project.