US President Barack Obama reserved his blunt but timely remark for the audience that is future of India. He wrapped up his three-day visit to India with a townhall event at Siri Fort auditorium in New Delhi.

His audience was mostly young and they were perfect listeners put an idea or the agenda to act. Obama touched one of India's most sensitive topics - religious freedom. "Your Article 25 (of the constitution) says that all people are 'equally entitled to freedom of conscience and the right freely to profess, practice and propagate religion."

"In both our countries, in all countries, upholding this fundamental freedom is the responsibility of government, but it's also the responsibility of every person."

India will succeed so long as it is not splintered on religious lines,” the US president told the young.

He tempered the caution with hope. “Young Indians are not only going to define the progress of this country, they are going to shape the world,” he said.

"The dreams of those who do menial jobs are just as worthy as ours. Luckily we live in countries where they can dream. In India and US, the grandson of a cook can be president, son of a dalit as president, tea-seller a prime minister," Obama said.

His three-day visit is being seen as a bid to forge a relationship that would help balance China's rise by catapulting democratic India into the league of major world powers.

A day after he became the first US president to attend Republic Day parade, Obama described the relationship between India and the United States as potentially "one of the defining partnerships of the century".

During the visit, the two sides sealed a clutch of deals to unlock billions of dollars in nuclear trade and deepen defence ties, with Obama pledging $4 billion in investments and loans to release what he called the "untapped potential" of a partnership between the world's largest democracies.

Most significant was an agreement on issues that, despite a ground-breaking 2006 pact, had stopped US companies from setting up nuclear reactors in India and had become one of the major irritants in bilateral relations.

"America wants to be your partner in igniting the next wave of Indian growth, as India pursues reforms to encourage more trade and investment, we'll be the first in line," he said.

“I am optimistic about our future, we vote in free elections, reach for heights, respect human rights. Imaginations beyond our lives,” said Obama.

At the Tuesday’s address, Obama introduced Vishal,16, who he met at Humayuns Tomb in 2010. He says Vishal is an example of young talent with aspirations to study.

The town hall meeting at south Delhi's Siri Fort Auditorium was the last engagement on Obama’s itinerary during his visit to India.