US President Barack Obama's began his speech with a Namaste and "bahut dhanyawaad (many thanks)" as he began townhall at Delhi's Siri Fort auditorium.
He is addressing about 2000 young people who cheered in delight when he said "Senorita..bade bade deshon mein..you know what I mean".
"India's yuth and idealism fill me with hope. India and US could have a defining partnership," Obama said.
"America wants to be India's partner as you protect the health of the people & the beauty of the nation. We want to be partner as you help improve the health of people from backwaters of Kerala to banks of Ganga," Obama said.
After his speech on 'India and America: The future we can build together', Obama will take questions from the audience of at least 2,000 people, including members of the strategic affairs community and students.
The theme of Obama's public address is in tune with the India-US vision statement, Chalein Saath Saath, unveiled in Washington during Prime Minister Narendra Modi's visit in September last year.
Backstage, Obama is expected to meet Nobel laureate Kailash Satyarthi.
After his speech at Siri Fort, Obama and the First Lady would leave for Saudi Arabia where he would meet the new Saudi king and personally expresses his condolences over the death of King Abdullah Abdullah.
The three-day visit of the US president has seen a mix of symbolism and significance where the bonhomie between Obama and Modi was on ample display and the two countries signed a slew of deals.
On Sunday, the two leaders announced plans to unlock billions of dollars in nuclear trade and to deepen defence ties. Other deals ranged from an Obama-Modi hotline - India's first at a leadership level - to financing initiatives aimed at helping India use renewable energy to lower carbon intensity.
On the second day of the visit, Obama attended the Republic Day parade and later, along with Modi, took part in India-US CEO roundtable.
Modi and Obama will also jointly address monthly radio programme 'Mann ki Baat' on state-run All India Radio on Tuesday.
Obama's visit--at Modi's personal invitation--marks the latest upturn in the bilateral relationship that saw a low point just a year ago.
(With inputs from PTI)