Several residential and commercial neighbourhoods in Chennai city were flooded with water due to heavy rains.
The rainfall has been termed heaviest since 2015. It occurred as a result of a low pressure over the Bay of Bengal.
People living on the low-lying banks of the surplus canal were issued alerts to shift to higher elevation areas.
The government is expected to release excessive water from Puzhal reservoir and Chembarambakkam reservoir.
The rain intensity
Rain recorders showed that the city and suburbs received 21.5 cm and 11.3 cm rains respectively by 8.30am on Sunday.
Similar episode of heavy rains was witnessed in 2015 when the city received 24.6 cm rainfall in 24 hours, breaking a previous record set in 2005.
The maximum rainfall received by the city in 24 hrs was in November 1976, when it had received 45.2cm of rainfall.
Role of north-east monsoon
Coastal districts of Tamil Nadu receive 60% of the annual rainfall and interiors 40-50% of the annual rainfall from the North East monsoon.
Chennai receives majority of its rainfall during the months of October, November and December in form of North-east monsoon.
Other states depend on south-west monsoons for their rains but Tamil Nadu banks on North-east monsoon for sufficient rains.
The south-west monsoon ensures that ground water level is maintained in the state after dry months. The North-east monsoon elevates the ground water table.
There is a likelihood of low pressure over the Bay of Bengal travelling towards northern Tamil Nadu coast with moderate rain in the coming days.
There is a likelihood of winds blowing off the Tamil Nadu coast and south Andhra Pradesh coast in the upcoming days.