A view of submerged market and houses due to floods at Panadala, on August 18, 2018 in district Pathanamthitta, India.

Some 800,000 people have been displaced and over 350 have died in the worst flooding in a century in southern India's Kerala state, as authorities rushed to bring drinking water to the most affected areas, officials said Sunday.

At least two trains carrying about 1.5 million liters (400,000 gallons) of water were moving to the flooded areas from the neighboring states of Madhya Pradesh and Maharashtra, Indian railway official Milind Deouskar said, according to the Press Trust of India news agency.

Thousands of rescuers were continuing efforts to reach out to stranded people and get relief supplies to isolated areas by hundreds of boats and nearly two dozen helicopters, said P.H. Kurian, a top disaster management official in Kerala. He said weather conditions had improved considerably and expected the nearly 10,000 people still stranded to be rescued by Monday.

An estimated 800,000 people were sheltered in some 4,000 relief camps across Kerala, Kurian said.

Weather officials have predicted more rains across the state through Monday morning.

The downpours that started Aug. 8 have triggered floods and landslides and caused homes and bridges to collapse across Kerala, a picturesque state known for its quiet tropical backwaters and beautiful beaches.

Officials estimate that more than 10,000 kilometers (6,200 miles) of roads have been damaged. One of the state's major airports, in the city of Kochi, was closed this past Tuesday due to the flooding. It is scheduled to remain closed until Aug. 26.

The Indian government said a naval air base in Kochi will be opened for commercial flights starting Monday morning.

Prime Minister Narendra Modi inspected the flooded landscape from a helicopter on Saturday and met with the state's top officials, promising more than $70 million in aid. While the central government has dispatched multiple military units to Kerala, state officials are pleading for additional help.

Officials have put initial storm damage estimates at nearly $3 billion.

At least 250 people have died in the flooding in a little over a week, with 31 others missing, according to Kurian. More than 1,000 people have died in flooding in seven Indian states since the start of the monsoon season, including over 350 in Kerala.