A senior official from the Water Resources and Ganga Rejuvenation Ministry said indigenous species such as oak, spruce, fir and walnut will be planted along the course of the Ganga, which provides water to over 40 percent of India's population across 11 states, to ensure more water in the river.
"Trees like walnut and oak, which are native to the Himalayas, absorb water and then release it slowly," a senior official from the ministry told IANS. "This ensures recharging of local water bodies and high water level in the soil. This in turn ensures that the water level in the river remains normal," said the official.
Explaining the procedure, he said if the water level in local river bodies is maintained, this in turn maintains moisture in the soil.
"When the soil is moistened, it will not absorb the river water; hence the water level in the river will increase," the official told IANS.
"The water retained by these trees also gives birth to several springs which contribute to many tributaries of the Ganga," said the official.
Over 2,500 km long, the Ganga flows through one of the most populated regions of the Indo-Gangetic plain, supporting a population of more than 400 million, almost a third of India's total. Deified by millions of Hindus, more than Rs.5,000 crore (over 800 million USD) has been spent on cleaning the Ganga in the past 28 years - but with little effect.
According to experts, the Himalayas saw massive replacement of flora during British rule, when local trees were replaced with commercially profitable pines.
Oak is regarded to be people's best friend in the Himalayas due to its water retention capability.
Pine trees, on the other hand, do not retain much water. Moreover their needles are known for their acidic content, which also affects soil fertility.
"The Ganga can be cleaned only when there is water in the river. The plantation drive is one of the steps to ensure this," the official noted.
Well-known environmentalist Anil Joshi welcomed the move and said focussing on the Ganga's catchment area is very important for any long-term change in the river.
"Ganga is a group of rivers. It is not only snow fed, but many of the tributaries also get a lot of water from rain. If there is a green cover with water retaining species, it will make a huge difference," said Joshi, who heads the Dehradun-based Himalayan Environmental Studies and Conservation Organization (HESCO).
"There are two groups of trees. In the upper reaches it is the oak and when you come down, there is the sal group of trees. These are all trees with broad leaves," the Padma Shri-winning environmentalist told IANS on phone from Dehradun.
He added that replantation of indigenous trees will also help solve the problem of floods as a higher amount of rain water will be absorbed.
The cleaning of the Ganga first began in 1974 when India first tried to tackle river pollution through the Water Pollution Act. The Ganga Action Plan was launched in 1986 and was in 1994 extended to the Yamuna, the Gomti and other tributaries of the Ganga.
The second phase of the Ganga Action Plan was launched in 2000 and the National Ganga River Basin Authority was created in 2009.
The Modi government has now launched the Clean Ganga Campaign to draft an elaborate plan for cleaning and rejuvenating the river from the Himalayas to Ganga Sagar in West Bengal, where it empties into the Bay of Bengal.
The government is making long- and short-term plans to clean up the river and it will take at least three years for the final plan to emerge.
The short-term goals include safe disposal of religious material in the river and controlling industrial discharge. In the medium-term, the ministry will try to control the flow of fertiliser from fields, while stopping the flow of sewage into the river is one of the long-term goals.