Torrential rains and landslides have killed at least 24 people in southern India, with the authorities opening the shutters of 24 water reservoirs in an unprecedented move to prevent potentially disastrous breaches.
The state meteorological department forecast the rains to continue on Friday and return on Monday.
The June-September rains in Kerala state have cost 175 lives and damaged crops worth 3.42 billion Indian rupees ($A67 million) across 26,824 hectares since their onset on May 29, an official at the Kerala State Disaster Management Authority (KSDMA), who did not wish to be identified, said.
Tens of thousands of people have been displaced, several are missing, with incessant rains for more than 48 hours in some areas inundating hectares of low-lying land, authorities said.
The National Disaster Relief Force and the armed forces are helping in rescue and relief operations.
Chief Minister Pinarayi Vijayan said the opening of 24 dams is unprecedented and showed the seriousness of the situation.
The state, which has 44 rivers, witnessed its worst floods in 1924 following torrential rains.
"The situation is grim, especially in the coastal parts of Kerala, given the continuous rains," said State Relief Commissioner and Convenor of KSDMA, PH Kurian.
With its sweeping coastline, riverboats and tea plantations, Kerala, about the size of Bhutan, has become a leading tourist destination, promoting itself as 'God's Own Country', and has seen a boom in infrastructure.
"Wetland refilling, encroachment and unauthorised construction in river banks and conversion of paddy fields have affected the flow of water, leading to stagnation and flash floods," another official at KSDMA said on condition of anonymity.
