Gandhi also said both old and the young leaders will be loved and respected in the Congress and find a place.
Rahul Gandhi said, "Elections are around the corner".
Mayawati questioned the "silence" of senior BJP leaders, including the Prime Minister, on the matter.
Projecting the Congress as a comeback force, Gandhi said: "Congress surpassed expectations in Gujarat assembly elections and you all will witness the change in Madhya Pradesh, Karnataka, Chhattisgarh, Rajasthan where we will win followed by the 2019 general elections".
He also sought to boost the morale of the party workers by praising them as "sher ka baccha (tiger cubs) and "soldiers of truth" who would challenge and defeat the "hatred and lies" spread by Modi and the RSS. Congress workers will not leave the side of truth".
Former Prime Minister Manmohan Singh, in a reference to the dissent in judiciary, said, "Constitutional institutions are facing a threat under the current government".More news: Washington in uproar over 'disgusting' White House Correspondents' dinner comedy routine
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The well-attended rally at Ram Lila Maidan came nearly a year before the next Lok Sabha polls and signalled Gandhi's intention to build up electoral momentum with sharp attacks on Modi and his government. "It is clear from this that if Parliament does not function, it can pose danger to the democracy in the country".
Gandhi said Dalits, minorities and women in every state are facing atrocities due to BJP rule and yet Modi says nothing and takes no measures to nullify it.
Rahul has been more forthright in condemning caste discrimination than any other Congress president, although his party can not disown responsibility for such practices continuing seven decades after freedom, a period the country mostly spent under Congress rule. Even though, Rahul Gandhi has taken over the reigns of the party but no significant achievements have been made by the party so far. "Instead he destroyed small companies with his demonetisation and GST moves", said Rahul.
He also spoke on Modi's China visit saying the Prime Minister and President Xi Jinping are having a discussion without an agenda.
The prime minister had promised to give two crore jobs per year and the people trusted him, but after four years of his government, there is widespread unemployment, he said. Our Prime Minister makes a lot of speeches. "The manner in which the Modi government is functioning, it can also pose a threat to democracy in the country".
He alleged that farmers were under stress, but their loans were not written off by the government, which "waived" the debts of corporate houses. This rally is not of the Congress but to reflect the feelings of the masses.