Aug. 27 (Bloomberg) -- India's Prime Minister Manmohan Singh will undertake an aerial survey tomorrow of flood-hit areas in Bihar state, where more than 42 people have been killed and about 1.1 million people are marooned.

``This is not a normal flood,'' Bihar Chief Minister Nitish Kumar told reporters in New Delhi today, after meeting Singh. ``It's like a catastrophe.''

Rains in Bihar state caused the Kosi river to swell, breach the embankment and change course, resulting in the inundation of villages and towns. The monsoon, which accounts for four-fifths of the country's annual rainfall and runs from June to September, has caused these flash floods since its arrival on May 31.

As many as 2.5 million people in 15 districts have been affected by the floods, Kumar said. ``Our top priority is to evacuate the marooned people,'' he said.

The floods have damaged roads, and hit water and electricity supplies. Railway tracks have been submerged and essential commodities, including food, are being transported by boat, the United Nations Children's Fund, or Unicef, said in a release.

About 227,081 houses have been damaged because of the floods in the state, the federal government's National Disaster Management unit said in a report. About 113,889 people have been evacuated, it said.

Kumar today sought ``immediate'' federal assistance of 10 billion rupees ($229 million) and 100,000 tons of food grains, preferably rice, for the affected people. The Bihar government also sought boats and tents to evacuate the flood victims and shelter them, the chief minister said.

``The evacuated people may have to be kept in safer areas for a period of two to six months, which requires a huge expenditure,'' Kumar said. The shifting of people to safer places has gained momentum since yesterday, he said.

Boats are engaged in rescue and relief operations and helicopters are dropping food to the affected people, Kumar said.

To contact the reporter on this story: Bibhudatta Pradhan in New Delhi at bpradhan@bloomberg.net.

Last Updated: August 27, 2008 10:24 EDT