Failure to deliver aid and compensation to millions of Pakistanis made homeless by the floods could lead to social unrest, especially as cold temperatures bite in the south Asian nation at the heart of US efforts to stabilize Afghanistan.

The southern Pakistan provinces of Sindh and Balochistan, still reeling from the record floods which began in late July, will take months to recover, according to the spokesman for the UN High Commissioner for Refugees (UNHCR).

“Local authorities are looking into how stagnant water can be pumped from villages, but this will be a massive undertaking and is likely to take time,” Adrian Edwards told a news briefing.

In Sindh, more than 1 million people were in some 3,200 camps or makeshift sites at the time of a UNHCR survey two weeks ago, but the numbers have fallen since, according to the agency. A further 60,000 displaced were in camps in Balochistan.

The floods, which rolled from north to south in an unprecedented tide of destruction, destroyed or damaged more than 1.7 million homes, official figures show.

Some 7 million people have shelter needs, including many who have returned to homes lacking a roof or electricity, said the International Organization for Migration (IOM), an aid agency playing a central role in the flood response.

“The immense scale of the disaster continues to pose a huge challenge to the government and aid agencies. We are still a long way from providing shelter to every flood victim,” said IOM regional representative Abdel Moneim Mostafa.

A United Nations appeal for $1.9 billion for Pakistan is only 39 percent funded, spokeswoman Elisabeth Byrs said.

“We still have a long way to go. The food security, health and camp management sectors are really under-funded,” she said.