Terming the flood situation in South Asia as worst in the living memory, the United Nations on Tuesday said around 20 million people in the region, including India, have been affected by the tragedy.

Thousands of people in India, Nepal and Bangladesh have lost their homes and livestock and will have to begin their lives from scratch when the flood waters recede, it said in a situation report.

The most urgent needs include shelter and access to fresh water, food, emergency medical supplies and basic household items, UNICEF said.

The UN World Food Programme is sending up to three months worth of emergency rations to some 60,000 flood victims in Nepal.

However, given the number of families affected and the remoteness of the impacted areas, the agency estimates that it will need some $1.5 million to meet the basic food requirements of the flood victims in the Himalayan country.

Some two million people were affected by devastating floods in Pakistan when Cyclone Yemyin struck the country in late June.