- Chief Minister had cardiac arrest last evening
- Neurologists monitoring her closely this evening
- She has shown 'some response' say sources
Here are the 10 latest developments in this big story:
Jayalalithaa's party, briefly lowered its flag to half-mast at its headquarter, then hoisted it again after Apollo Hospital said local channels' reports on her death were "totally baseless and false". The 68-year-old had a cardiac arrest last evening.
A brief riot erupted at the hospital after the incorrect television reports, and the police had to use lathis or batons to control the crowd of thousands which tried to rush past barricades.
Four doctors from Delhi's premier AIIMS institute have been sent to Chennai, and have examined the Chief Minister. "AIIMS doctors have seen her, there is a positive response and progress to the treatment," said AIADMK spokesperson C Ponnaiyan to NDTV, confirming what a top political leader from a different party told NDTV.
London specialist Dr Richard Beale, who had flown down earlier to supervise the Chief Minister's condition, said in a statement from the United Kingdom, "The situation is extremely grave". He told NDTV that the politician is now "on the most advanced level of support" but that the politician's "underlying conditions" complicate her recovery.
The Chief Minister is now being treated with ECMO or an Extra-Corporeal Membrane Oxygenation device, which means that she is being assisted in breathing and in heart functions.
Union Minister Venkaiah Naidu, who has been in Chennai since morning, met Apollo hospital doctors and has briefed PM Narendra Modi about Ms Jayalalithaa's health.
The police has blocked all roads leading to the hospital where hundreds of the Chief Minister's supporters have gathered to keep vigil just like they had months ago, disbanding only when doctors said she had recovered.
Security across the state has been reviewed as a precaution against violent or self-harming protests by lakhs of supporters of the hugely popular politician. Shops and petrol pumps closed early, and Chennai roads were deserted as the city worried about violence if the Chief Minister's condition worsens.
Just days ago, the Chief Minister was moved from the critical care unit of the hospital to a private room fitted with state-of-the-art equipment.
In a series of tweets last night on the politician's health condition, Apollo Hospital asked for prayers for the leader's recovery. Yesterday, hours before Ms Jayalalithaa's condition worsened, her party said that she was fully recovered and was due to decide on when to return to her home.