The Gangotri glacier, source of the river Ganges, has been receding at such an alarming rate that environmentalists fear that if urgent measures are not undertaken, a time may come when Ganges may just disappear. If environmentalists are to be believed, a dip in the holy Ganges for future generation of Indians could well become a thing of the past. The Gangotri glacier, source of the Ganges, is receding alarmingly and in a few hundred years will dry up considerably.

A recent study by the Geological Survey of India has confirmed the bad news. But the study adds that besides the receding glacier, it is also the flow of industrial toxics, dumping of solid wastes and dead bodies floating in the river that have all made the Ganges the most polluted water source of the subcontinent.

But what is of great concern is the fact that the Gangotri glacier, situated in the Uttarkashi District of Garhwal Himalaya, has been receding at the rate of 10-30 meters per year over the second half of this century. While the rate of retreat was nominal between 1935 and 1956, it started to increase rapidly after that.

In terms of the total area, the retreat was 2,530 square meters between 1935 and 1956. It increased by around two and a half times during 1956 and 1962 and five times from 1962 to 1971. The last survey carried out a couple of years ago showed that the recession has increased over ten times from its original readings.

Gangotri Glacier - 29 kilometers long, and two to six kilometers wide - sweeps like a gigantic highway through the heart of the mountains. It is the longest glacier in the Central Himalayas, with its snout just to the north of the Great Himalayan Range.

In the last 13 years, the glacial channel feeding the Ganges River has shifted 20 meters and has now changed track and the volume of water too is shrinking rapidly. Similarly, many parts of the ridge formed by rocks and debris over centuries have completely disappeared.

Largest Himalayan Glacier One of the largest glaciers in the Himalayas, Gangotri originates at 7,100 meters above sea level and descends to a height of 4,000 meters, covering around 143 square kilometers in northern and eastern India. Its estimated volume is 27.75 cubic kilometers. However, the length and volume of glaciers are not stable. They are dependent on mass balance, and therefore, on climate.

Periods of positive mass balance result in glacier growth, periods of negative mass balance result in recession.

The Gangotri glacier originates from snowfields where the ice is white with a bluish tinge. Towards the lower end, it takes the appearance of a mud stream, due to the rocks and debris which flow down with the glacier and get buried in the snowfields.

Over the years these rocks and debris, called moraines, have risen to become high natural walls on the sides of the glacier valley through which the river carves out deep gorges. Most of these moraines were deposited when the glacier had reached its prime in the Pleistocene period.