Ms Kumar, 72, said "freedom of press, social justice and the destruction of the caste structure" are at the core of the ideology that united the parties that have fielded her for President against the ruling BJP-led national alliance's nominee Ram Nath Kovind.
"There is a storm that two Dalits are pitted against each other for the President's post and the truth of our society is coming out. Whenever similar elections have happened in the past, there were candidates who fought but their religion or caste was never discussed. But today it has been highlighted," said Ms Kumar, a Dalit leader of the Congress from Bihar, whose selection by the opposition parties was seen as a counter to the BJP picking a Dalit leader Mr Kovind.
The opposition's strategy was to ensure that key members of the opposition bloc like Mayawati would not support Mr Kovind because he is a Dalit, who form a big chunk of the Bahujan Samaj Party leader's support base.
Ms Kumar described her battle with Mr Kovind as "one of ideology." The BJP and its allies, along with regional parties who have offered support have over 60 per cent of the vote and Mr Kovind is expected to win the presidential election with ease.
Attacked by senior BJP leader and union minister Sushma Swaraj for what the latter said was a biased tenure as Lok Sabha Speaker when the Congress was in power at the Centre, Ms Kumar said she had in fact been feted for being "unbiased not only by lawmakers from the then ruling party, but also the opposition" when her term ended.
Elections for President will be held on July 17 and votes will be counted on three days later.