India's government reached out this week to the millions of ethnic Indians living around the world, honoring their achievements and urging them to forge new alliances with their ancestral home by bringing in investment.

At a three-day spectacle of packaged nostalgia and homecoming that was billed as the largest-ever gathering of the "global Indian family," Prime Minister Atal Bihari Vajpayee offered dual citizenship to the Indian diaspora in the United States, Britain, Canada, Australia, New Zealand and Singapore and urged them to invest in India's economy.

Addressing a meeting of 2,600 "prominent Indian achievers" from around the world -- with the largest representation from the United States -- Vajpayee congratulated Indians overseas for adapting to their new homes while maintaining their "original Indian identity." He said their accomplishments in high technology, education, medicine and business have "dramatically changed the world's perception of Indians -- and, hence, of India."

For years, India looked upon the flight of its best and brightest as a debilitating brain drain. But as India opens its economy and envisions a larger role for itself in global politics, attitudes toward emigrants have shifted.

"With 20 million persons of Indian origin in 110 countries, India is no longer restricted to the subcontinent, it straddles the world," India's leading English-language newspaper, the Times of India, wrote in an editorial this week.

Indian economists estimate the diaspora's collective income at about $160 billion, almost one-third of India's gross domestic product. India hopes to tap into their wealth and clout in the way that China has done. According to the Federation of the Indian Chambers of Commerce and Industry, the Chinese diaspora contributes almost 60 percent of China's total foreign investment, while Indians abroad contribute 4 percent of India's foreign investment.

"No matter where they are, Indians carry India in their hearts. Their love for India can translate into investment," said Laxmi Mall Singhvi, a member of Parliament who headed a government committee to address the concerns of the diaspora. "But sentiment alone is not enough. India has to provide the necessary infrastructure and a business climate to make it viable."

To that end, the offer of dual citizenship would make it possible for ethnic Indians from other countries to live, work and buy property in India, though they would not be allowed to vote or run for office.

In the United States, about 1.7 million people of Indian ancestry have emerged as an influential and vocal ethnic group. In a steady migration since the 1960s, when Indians began moving to the United States in large numbers for education and better jobs, they have achieved enormous success in the business and professional world, notably playing a pivotal role in the high-tech industry. Their impact has been apparent in American culture as well, with Indian-directed movies such as M. Night Shyamalan's "The Sixth Sense" and Mira Nair's "Monsoon Wedding" hitting it big at the box office in recent years, and books by Salman Rushdie and V.S. Naipaul attracting wide readership and exerting significant influence.

The diaspora gathering here drew representatives of Indian communities from such far-flung countries as Trinidad, South Africa, Fiji, United Arab Emirates and Singapore. Political leaders of Indian descent from Canada, Britain, Singapore, Malaysia and other countries also attended.

Apart from investment, India regards prominent Indians around the world as its unofficial ambassadors, and Vajpayee acknowledged the role they played after India incurred tough international sanctions.

"When there was an effort to isolate India after our nuclear tests of 1998, you came forward to stand by India," Vajpayee said. "Your enthusiastic response helped us raise over four billion U.S. dollars when we needed it most."

Sitting in the audience was Shivraj Singh, 66, an Indian American from Maryland who migrated to the United States in 1958. He laments that his children do not speak any Indian languages and wonders why India is "so poor and dirty."

"We are 100 percent Americans today. But hidden somewhere beneath it all is our Indian identity," Singh said. "We would like to give back something to the country of our forefathers. A meet like this gives us an important platform to contribute to India's development."

As a start, Singh said the firm that he heads, which specializes in cancer research, will bring top American specialists to India this month for "transfer of knowledge and expertise."

Benzion Jacob, right, an Indian painter living in the United States, returned after 44 years for conference of emigrants, with his agent, Victoria Lempicka.