Chief Minister Jayalalithaa, who reviewed the situation with officials on the situation in the city which was battered by an extraordinary heavy spell of rain this morning, said the armed forces had been alerted to immediately provide assistance in conjunction with the civil administration.

The city experienced 21 cm of rain in just five hours, while the 24 hours ending 8.30 am registered 27 cm, she said.

• Images: Hard rain pummels India

The unprecedented downpour had resulted in heavy water-logging and in some places trees had fallen and blocked the traffic. She directed the officials to remove roadblocks immediately and restore traffic.

The State Electricity Board, as a precautionary step to avoid deaths due to electrocution, has disconnected power supply wherever heavy flooding had taken place, Jayalalithaa said, adding she had directed the EB to restore supply after ensuring safety.

About 50,000 people had been evacuated from low-lying areas and accommodated in relief centres opened by the Chennai Corporation and food packets would be distributed in these centres, she said.

• Heavy downpour shuts Chennai international airport

Seven ministers and eight IAS officers had been deputed to undertake relief work on a war-footing, she said.

She also visited many flood affected areas in the city.

Claiming that the flood situation in other parts of the state was improving, Jayalalithaa said she was deputing ministers to supervise relief work in the districts.

O Pannerselvam, C Ponnaiyan, D Jayakumar, N Thalavai Sundaram, Anitha R Radhakrishnan, R Viswanthan and K P Anbalagan would be supervising relief work in Chennai, while Pollachi V Jayaraman, R Vaithilingam and M Radhakrishnan were being deputed to Nagapattinam, Thiruvarur and Thanjavur districts.

C V Shanmugam and S Ramachandran would supervise the relief operations in Cuddalore district and C Karuppasamy, Nainar Nagenthran, S M Velusamy and P Annavi would do so in Thiruchirapalli, Karur and Perambalur districts.

B Valarmathy, K Pandurangan and V Somasundram would supervise the operations in Kancheepuram, Thiruvallur and Vellore districts while P C Ramasamy, Vijayalakshmi Palanisamy, A Miller and Inbathtamizhan were being deputed to Salem, Namakkal, Erode, Dharmapuri and Krishnagiri districts, she said.