At least 188 people are now known to have died in floods in Tamil Nadu state since last month.
A depression in the Bay of Bengal has triggered rains in coastal areas.
Last month, non-stop rain for nearly a week brought the city to a standstill.
Two days of fresh rains have again led to massive flooding, so much so that flights from the city`s airport have been indefinitely suspended after flood waters entered the runway and tarmac areas on Tuesday evening.
Reports say some 400 passengers are stranded at the airport, and a number of flights have been cancelled.
More than a dozen trains have also been cancelled after flood waters inundated the tracks.
""The army and The National Disaster Response Force have been deployed in the city`s worst-affected southern suburbs to rescue people stranded in their flooded properties.
Reports say that power supply has been suspended in nearly 60% of the city`s neighborhoods.
Most of the main streets are waterlogged and schools were closed for the 17th day since November, reports say. Schools and colleges have been shut in six districts due to the rains.
Patients have been evacuated from a government hospital in the Tambaram area after flood waters entered the building.
Residents have taken to social media to offer accommodation, food and mobile phone recharges to citizens who are being forced to evacuate their properties.
"We only saw rains like this some 25-30 years ago when there was no electricity for almost a week. It has been raining since Monday night and there has been no respite. Everywhere you look, there is two to three feet of water,`` Ashok Modi, a resident of Sowcarpet area told BBC Hindi`s Imran Qureshi.
All the reservoirs around Chennai are full and the rivers are flooded with the excess waters released from the reservoirs, says the BBC Tamil`s Muralitharan in Chennai.
Thousands of people who were living on the banks of these rivers have been moved to temporary shelters.
The meteorological office says "scattered to heavy" rains are expected to continue for the next three days.
