In the latest issue of party mouthpiece Congress Sandesh, party president wrote, "On this sombre occasion, let us reflect on and recall the simple and austere manner of her living and conducting herself. Let us also resolve to continue to be guided by her."
Sonia Gandhi goes on to speak on Indira Gandhi's contributions to the country and its progress.
"Her contributions are numerous and continue to resonate. It was her bold political leadership that made India self-reliant in the production of wheat and rice that brought prosperity to lakhs and lakhs of farmers, transforming rural India.
"It was her compassionate leadership that gave the highest priority to policies and programmes for the welfare and wellbeing of the weaker sections of society," Sonia writes.
On Oct 31, 1984, Indira Gandhi was shot dead by her Sikh bodyguards which led to thousands of Sikhs being killed in the anti-Sikh riots which was triggered off to avenge the prime minister's assassination.