Chennai has witnessed record rains over the last 48 hours and more is expected as the cyclone bypassed the Indian coast and moved towards Bangladesh on Wednesday.
With memories of the December floods in the city still fresh, the civic authorities have started massive emergency preparations.
"There have been warnings of very heavy rain, so we could not take chances ... we have learnt a lesson from the December floods," Chennai municipal commissioner Chandramohan told NDTV.
The civic authorities have deployed nearly 12,000 people across the city to conduct safety operations, and boats have been stationed at multiple locations for emergency rescue, said Chandramohan. Four teams of the National Disaster Response Force have been deployed in low-lying areas.
Sewage lines in Chennai have started overflowing in many areas due to rain caused by the cyclonic winds. "Water from subways is being pumped out to ensure free flow of traffic," Chandramohan said.
The authorities have also set up an emergency number - 1070 - to receive rainfall-related complaints.
Senior officers have been sent to other areas in the state where heavy rainfall is expected to continue. The state has kept around 25 boats on standby, and more have been brought in by the National Disaster Response Force.
On Tuesday, the government said Chennai and its neighbouring districts were expected to receive very heavy rainfall of more than 25 cm. Cuddalore, Villupuram, Thanjavur and Nagapattinam districts were expected to receive more than 12 cm rainfall.
Rains and floods for two consecutive weeks last year killed nearly 350 people in Tamil Nadu and had caused widespread destruction.
Besides Tamil Nadu, Andhra Pradesh and West Bengal are also witnessing heavy rains. Very heavy rainfall has also been predicted for Andhra Pradesh. Fishermen have been warned against going to the sea.