Around 400 passengers are stranded at the Chennai airport, where water has entered the runway, reaching the under carriage of aircraft. Flights cannot take off till the water level recedes, airport director Deepak Shastri told NDTV. Till 10 pm on Tuesday, nine flights had been cancelled. 13 trains have also been cancelled with water flooding rail tracks.

Two columns or 50 personnel of the Indian Army have been deployed in Chennai suburbs Tambaram and Oorapakkam. The Navy is on stand-by and the National Disaster Rescue Force or NDRF has sent ten teams, of which four are already in Chennai and the rest will fly in tomorrow.

Roads in various parts of Chennai are submerged and water has reportedly entered many homes. Residents reported power outage in various parts of the city. The Chennai zoo is flooded and officials had to walk nearly 4 km to reach it.

Schools were closed for the 16th day since November because of rains and half-yearly exams have been postponed.

People used social media to seek help from the buses, private cars and rooftops they were stranded in. Nearly 500 employees of the Mahindra World City were said to be stuck on the roads at Gunduvanchery.

Residents opened their doors to strangers again, offering food, shelter and even mobile recharges. A mall in South Chennai said it kept its doors open overnight for stranded people.

Prime Minister Narendra Modi spoke to Tamil Nadu Chief Minister J Jayalalithaa this evening assuring her of all help from the Centre. "Spoke to Jayalalithaaji on the flood situation in parts of Tamil Nadu. Assured all possible support & cooperation in this unfortunate hour," PM Modi tweeted.

Her party said Ms Jayalalithaa is monitoring the crisis "minute by minute". "Police, Fire and Rescue, National and State Disaster Forces and the Coast Guard have been kept ready for need-based evacuation of people from flood hit regions," the Chief Minister said.

There was 1049.3 mm of rainfall in Chennai in November. Rain is expected to continue for the next four days, said the met office. Tamil Nadu has been lashed for the second time in three weeks by what is said to be the worst rain in nearly 100 years.