A depression over Bay of Bengal bypassed Chennai and moved towards Bangladesh on Wednesday, but triggered heavy rains in parts of Tamil Nadu, Andhra Pradesh and West Bengal.
A cyclone warning was issued for northern areas of Tamil Nadu and southern parts on neighbouring Andhra earlier in the day.
Four National Disaster Response Force (NDRF) teams arrived in Chennai on Wednesday with 24 boats. The Tamil Nadu capital had suffered damages and witnessed flooding in its worst rainfall in 100 years last November.
An Indian Administrative Service (IAS) officer was appointed to supervise flood-related relief efforts and safety measures in each of Chennai’s 30 zones.
Officials said they deployed motor pumps near subways - such as Ganeshapuram, Perambur High Road and the Villivakkam Redhills Subway - prone to flooding. Medical teams were formed to assist affected residents.
The weather office said squally wind speed reaching 55-65km will prevail along and off north Tamil Nadu and Puducherry in the next 24 hours.
Sea condition will be rough to very rough, and fishermen have been advised not to venture out to sea during next 48 hours.
Weather blogger R Pradeep John posted preliminary rainfall figures on Facebook, saying Chennai “witnessed it’s wettest one day May month rainfall since 1995 (sic)”.
The commissioner of revenue administration said an emergency hotline number of 1070 can be contacted for any rain-related grievance.