PM Modi said Onam is a festival associated with positivity, vibrancy, brotherhood, and harmony.
Leaders cutting across political lines extended their Onam greetings to Keralites on Saturday.
President Ram Nath Kovind, Vice President M Venkaiah Naidu, Prime Minister Narendra Modi, Union Minister Amit Shah, Congress leaders Rahul Gandhi and Priyanka Gandhi, Delhi Chief Minister Arvind Kejriwal are among those who wished the people of Kerala.
"Onam greetings to all our fellow citizens! This festival is a celebration of the new harvest. It highlights the tireless work of farmers. It is an occasion to express gratitude to mother nature. I wish to progress and prosperity for all fellow citizens," the President of India tweeted from his official Twitter handle.
PM Modi said Onam is a festival associated with positivity, vibrancy, brotherhood, and harmony. "I pray for everyone's good health and wellbeing," Prime Minister tweeted.
Amit Shah, who had earlier in 2016 created a furore in Kerala for wishing "Vamana Jayanthi" on Saturday tweeted that Onam signifies peace and harmony.
"On this auspicious festival, I extend my warm greetings to all our Malayalee sisters and brothers around the world. May the flavours of Sadya and the musical beats of Pulikali bring an abundance of joy and prosperity to all. Happy Onam!," he said.
Arvind Kejriwal and Priyanka Gandhi too took it to Twitter and wished all Keralites "a very Happy Onam".
"May the spirit of Onam for an egalitarian society prevail. Wishing you all a very Happy Onam," Priyanka Gandhi tweeted.
In a video message, Rahul Gandhi said Onam is a very important festival for everyone.
"It's a day of happiness, of joy, of introspection and I would like to thank you for allowing me to be part of it... I hope you all have a joyous and wonderful day," Rahul Gandhi said.
West Bengal Chief Minister, Mamata Banerjee, wished everyone a very happy Onam and said "May this festival bring peace and prosperity to all".
Keralites across the world on Saturday celebrated Onam, a festival connected with the return of Asura (demon) King Mahabali, under whose reign everyone lived in happiness and equality.
According to folklore, envious of his popularity, the Devas (Gods) sought the help of Lord Vishnu to get him banished into the netherworld but before going down, Mahabali secured a boon from Vishnu to visit his subjects every year on Thiruvonam Day, which this year falls on August 21.
The demon king's annual visit is celebrated by Keralites, who lay their front yards with floral carpets, wear new clothes, and prepare a sumptuous feast.