Rainfall will reduce further over the next five days, the met department said. Heavy rain is likely at one or two places in Idukki, Konnur and Kozhikode districts.

The National Disaster Management Authority tweeted to say that floodwater in some areas have started receding. "Water levels show falling trend. Some hydrographs from @FFM_CWC," their tweet read.

With the airport in Kochi still flooded, the Naval air base in Kochi is ready for commercial flights to begin operation from tomorrow. Naval Air Station INS Garuda has received clearance to operate passenger planes and the Navy spokesperson tweeted to say all arrangements are in place.

Union minister JP Nadda said while no outbreak of communicable disease has been reported, health experts say "once the flood water starts receding, the environment would be conducive for epidemic prone diseases". The state has asked to check for "early warning signs of an outbreak," the health ministry said in a statement.

Kerala Chief Minister Pinarayi Vijayan said repairing the havoc wreaked by the worst flood in a century will require at least Rs 2,000 crore in immediate assistance.

PM Modi, who was taken by helicopter over inundated farmland and villages, pledged Rs 500 crore in central aid and promised more helicopters, boats and other equipment needed to expand the rescue operation in the still unfolding emergency.

Hundreds of thousands converged in halls and auditoriums of schools, temples, churches, and mosques with little or no toilet facilities. Some people in the relief camps were finding it difficult to access food and water. Videos on social media showed groups of people breaking open shops to take food.

Rescue workers have yet to reach many flooded areas, some too narrow for boats to navigate.Helicopters have been dropping emergency food and water supplies. Special trains carrying drinking water and rice have been sent to the state.

The South Eastern Railway ran two special trains from Ernakulam to Bengal to evacuate stranded people this evening, a spokesman of the railways said. Tourists and migrant workers from Bengal have been stranded in Kerala due to the floods.