The Delhi government on Monday asked people living near the rising Yamuna to move to safer areas.
The government advisory came as the river's water level rose to 204.16 metres - 67 centimetres short of the danger mark.
"Our department will start evacuating people. All preparations are in place to deal with a flood-like situation," irrigation and flood control minister AK Walia said.
"The water level has reached 204.16 metres and the danger mark is 204.83," said an official.