The Tamil Nadu government has declared a holiday on Wednesday following Karunanidhi's death and said the state will observe 7-days mourning.
The Centre has decided to accord state funeral to the DMK chief.
The national flag will fly at half mast in Delhi, all state capitals and across Tamil Nadu tomorrow as a mark of respect to DMK chief M Karunanidhi, who passed away today, the Home Ministry announced.
The government of India will observe state mourning across the country tomorrow and there will be no official entertainment during the day, a Home Ministry spokesperson said
The veteran of Dravidian politics was shifted to the hospital on July 28 from his Gopalapuram residence following a dip in his blood pressure and he was under treatment in the Intensive Care Unit ever since.
Prime Minister Narendra Modi mourned the death of DMK president M Karunanidhi, describing him as a prolific thinker and a deep-rooted mass leader who stood for regional aspiration and national progress.
"I am deeply saddened by the passing away of Kalaignar Karunanidhi. He was one of the senior most leaders of India. Kalaignar Karunanidhi stood for regional aspirations as well as national progress. He was steadfastly committed to the welfare of Tamils and ensured that Tamil Nadu's voice was effectively heard," Modi said in his tweets.