The district administration said there is no cause for alarm and all arrangements to evacuate people are in place.
The area of the lake at an altitude of 11,000-ft has increased to nearly 3.5 sq km and the depth to 20 to 30-ft and in case it bursts, downstream areas will be flooded, locals said.
Allaying fears, the administration said the size of the lake is not too big and all arrangements to evacuate people and provide them food and essential commodities are in place.
The lake was formed near Shangni Pin valley and it appears the flow of water has increased due to melting of snow and glaciers in higher reaches.
The huge quantity of debris and mud carried by water along the narrow river has already flooded and damaged the 4-km road and the area where the lake has been formed.
The district administration has requisitioned choppers which made three sorties yesterday and today to evacuate the tourists.
Additional Deputy Commissioner Hessinh Negi said the choppers also carried essential commodities for the stranded people and there is no cause for alarm.
He said some 12 people, eight of them foreigners, had been stuck up in the area and most of them had been evacuated.
