A.P.J. Abdul Kalam, Who Pushed a Nuclear India, Dies at 83

New Delhi: India's 11th president, A.P.J. Abdul Kalam, whose role in advancing India's nuclear program made him one of his country's most beloved figures, died on Monday after collapsing at an event where he was to deliver a lecture. He was 83.

The cause was cardiac arrest, doctors told NDTV, an Indian news channel.

Kalam, an ardent nationalist nicknamed "the Missile Man of India," was embraced by both the left-leaning Indian National Congress party and the right-wing Bharatiya Janata Party. His death brought an outpouring of mourning on Monday from across the ideological spectrum at a time of intense political polarization in India.

Born into a humble South Indian family - his father rented a boat to fishermen working the strait between India and Sri Lanka - Kalam was singled out as a promising student and went on to study aeronautics.

A practicing Muslim, he involved himself in the country's broader culture, studying Indian classical music and, a biographer said, committing to memory sections of the Bhagavad Gita, one of Hinduism's most sacred texts.

"My mind is filled with so many memories, so many interactions with him," Prime Minister Narendra Modi wrote on Twitter. "Dr. Kalam enjoyed being with people; people and youngsters adored him. He loved students and spent his final moments among them."

A similar tribute came from P. Chidambaram, a prominent leader in the Indian National Congress and sharp critic of the current government. "In recent history, only a few had endeared themselves to the young and old, poor and the rich, and to people belonging to different faiths," he wrote of Kalam.

Kalam's celebrity could be traced to 1998, when India detonated five nuclear devices in a matter of days in the country's northwestern desert, to widespread international condemnation.

Described at the time as an "impish, shaggy-haired bachelor" of 66, he was one of the most exuberant boosters of the country's nuclear program. In the years leading up to the tests, he was so frustrated with the government's reluctance to approve them that he threatened to leave his post.

He used the spotlight to urge India to build up its military strength and to free itself from the threat of domination by outside forces.

"For 2,500 years India has never invaded anybody," he said at a news conference after the tests. "But others have come here. So many others have come."

Even after he was elected president four years later, Kalam made it a priority to meet one-on-one with young people, setting a target of 500,000 such exchanges for his five-year term. Many came to know him as "Kalam Chacha" ("Kalam Uncle"), an endearment previously bestowed on Jawaharlal Nehru, India's first prime minister.

Kalam's speeches were ebulliently motivational.

"We must think and act like a nation of a billion people, not like that of a million people," Kalam once said. "Dream, dream, dream!"

Avul Pakir Jainulabdeen Abdul Kalam was born on Oct. 15, 1931, on an island off Tamil Nadu. He had said that his interest in aeronautics began when he was a small boy, delivering a local Tamil newspaper, and noticed an article about the Supermarine Spitfire, a fighter jet used by the British in World War II.

He studied aeronautical engineering in the hope of becoming a fighter pilot but was eliminated from contention in a final round of qualifying interviews. He took an entry-level job at Hindustan Aeronautics instead and was later hired by the Indian space research organization and defense research and development organization. There he helped develop India's first satellite launch vehicle and guided missile program.

Kalam spent little time outside India. For him, it was a point of pride that India had developed its bomb without much help from foreign powers. And he described himself as thoroughly Indian.

"I am completely indigenous!" he told The New York Times in 1998.

By early morning on Tuesday, there were few political figures in India who had not released an expression of grief.

"He was the best human being I came across," Pratibha Patil, his successor as president, told Times Now, an Indian news channel. "I feel very sorry."