Aid agencies are asking the UK public to dig deep to help ease the suffering faced by up to 28 million people affected by flooding in South Asia.
Charities have warned there will be no quick fixes
Christian Aid and Save the Children have launched appeals with the Catholic Agency for Overseas Development (Cafod) pledging extra funds.
Most water sources in affected areas of India, Bangladesh and Nepal are said to be contaminated or submerged.
Save the Children has warned there will be no quick fixes.
Director of emergencies Gareth Owen said: "This is the worst flooding we've seen for nearly a decade and it will affect children for months to come.
"Children are already facing a lack of food and water and are at risk of disease from dirty flood water."
THE ASIAN MONSOON
Monsoon winds blow north-easterly for one half of the year, and from the south-west for the other half
South-westerly winds bring the heavy rains from June to Sept
Winds arrive in southern India six weeks before the north west
Annual rainfall varies considerably
The charity is aiming to raise £2m to supply food, drinking water, shelter and medicines across the region.
Two weeks of monsoon rain have displaced millions and left 36 dead.
India is the worst affected country. The United Nations (UN) said some 20 million people in the states of Assam, Bihar and Uttar Pradesh had been hit by the floods.
And some eight million people are affected in Bangladesh together with another 300,000 people in southern Nepal, the UN added.
Cafod has pledged a further £200,000 to help those affected, particularly in Bangladesh.
The charity's Pauline Taylor-McKeown said millions of people had lost their homes through the flooding.
"Work is just beginning and it is clear recovery will take a long time," she added.
Meanwhile, the World Health Organization (WHO) and Unicef have warned that stagnant waters are "a lethal breeding ground" for diseases such as malaria and dengue fever.
Relief supplies are being distributed but the scale of the disaster has dwarfed efforts to help victims.