Mandela was awarded India's highest civilian award, the Bharat Ratna, in 1990, a rare honor for a non-Indian citizen.
The Peace Summit was held on the eve of the High-Level General Assembly session to commemorate the birth centenary of Mandela, who led the successful fight against apartheid in South Africa and ended white minority rule. He later became its president.
The declaration paid tributes to Mandela's humility, forgiveness and compassion, and his contribution to the struggle for democracy and the promotion of peace.
Sushma Swaraj said India cherished the close relationship and partnership with Africa and its people.
"They made efforts to overcome the divisive and narrow identity politics (and) to turn diversity of a society into its strength instead of weakness," she said.
Secretary-General Antonio Guterres hailed him as "one of humanity's great leaders" and recalled that "everywhere, he was a champion for peace, forgiveness, humility, compassion, dignity and human rights."
General Assembly President Maria Fernanda Espinosa Garces said that Mandela's legacy gave hope to a world facing conflicts, oppression of minorities and threats of proliferation of chemical, biological and nuclear weapons.
South African President Cyril Ramaphosa said the peace summit was an opportunity for global leaders to reflect on peace and to take steps to end the wars.