The Indian Meteorological Department forecast light to moderate rain in most affected areas, with occasional flooding of roads and low-lying areas in some places.

"The worst is over and occasional rains will happen," said Pradeep John, an amateur forecaster who is widely followed in Tamil Nadu, India's worst-affected state.

The rain, brought by a low pressure, killed 20 people in the neighboring island nation of Sri Lanka, most of whom drowned, while landslides injured five, officials said on Wednesday.

Five people were killed in Tamil Nadu.

Many parts of the state capital Chennai, which is India's auto manufacturing center, were waterlogged on Thursday and government officials used pumps to drain water that had stranded some residents waist deep.

Thousands of people in low-lying areas were moved to safety, officials said.

Many schools and colleges in Tamil Nadu remained closed while some train services were still suspended.