They're called the Sundarbans.
And they're part of the world's largest mangrove forest, stretching across the border between India and Bangladesh.
Mangrove trees help stabilize the river deltas there and provide habitat for an array of animals, including the famous swimming Bengal tigers, some of the last of their kind in the world.
On December 9th a tanker in the area disgorged its oily cargo after a collision with another ship.
Now 350 square kilometers of this riverine environment are coated with more than 350,000 liters of thick fuel oil.
Cleanup efforts have been performed mostly by local people so far, scooping up the sludge with whatever tools are at hand.
And as past oil spills around the world have shown,once oil is in marsh sediments it takes decades to come out, with all kinds of negative impacts on flora and fauna.
The United Nations is now organizing a more coordinated response.
True, the affected area of the Sundarbans is just a small part of the 10,000-square-kilometer mangrove forest.
Still, it's not yet known what impact the oil will ultimately have on fisheries and watery plants that millions of people rely on for food.
Also at risk are endangered animals like river dolphins.
But it is clear that an area designated a world heritage site by UNESCO has been tarred.
1.provide for 为…提供； 供养
Both the petitioner and respondent provide for the upkeep of the children.
The education authorities have to provide for children in need.
2.come out 出来；出现
They would always come out and warm up the audience.
"Keep quiet, or they'll all come out," they warned him.