M Karunanidhi hospitalised In picture: M Karunanidhi.IANS

DMK chief M Karunanidhi was readmitted to Cauvery hospital in Chennai just after 11 pm on Thursday. He underwent "tracheostomy to optimise breathing. He is stable and on antibiotics," said the hospital. 

"DMK President and former CM of TN, Dr Kalaignar Karunanidhi has been readmitted at Kauvery hospital, today with breathing difficulty due to throat and lung infection. The treatment has been initiated to clear his infection," the hospital said. They also said that he was stable and is being treated. 

"He (Karunanidhi) had some lung infection and breathing difficulty, he is much better now," said his daughter, Kanimozhi. 

When late AIADMK chief J Jayalalithaa was admitted to the hospital, reports had said that it was a throat and lung infection.

Karunanidhi was readmitted only a week after his visit to the hospital. DMK sources told TNM that his situation is stable and he was not critical unlike social media speculation. 

"At his age, having an infection can be worrisome, so, he was taken to hospital," a source close to Karunanidhi said. 

Another source told TNM he had been unable to eat and developed other complications because of which he was taken to the hospital. 

The 92-year-old was taken to Kauvery Hospital on December 1 for treatment to allergic reactions to drugs. The hospital had then said that he was admitted for "optimization of nutrition" and "hydration." 

The DMK chief has reportedly been unwell for many weeks now. He had announced in October 2016 that MK Stalin will take over the party after him. However, he had also said that he won't be retiring anytime soon and did he hand over the party's reigns to his son. 

"Even when Stalin was very young, he formed the Youth Wing and worked tirelessly. Then, from the time of MISA (when he was jailed under the Maintenance of Internal Security Act for protesting the emergency in 1975) when he went to prison, he has undergone torture, worked by himself and attained the position of the future leader of the DMK step by step. Given this, he is today my political successor," he said in an interview.