5. Yamuna River, India Yamuna, the largest tributary river of the Ganges, originates from the yamunotri glacier in the Lower Himalayas. It passes through several states of north India before merging with the Ganges at the Triveni Sangam. The river meets the need of nearly 57 million people and accounts for 70% of Delhi's water supplies. But this river is now affected deeply by pollution as millions of household garbage, municipal disposals and soil erosion due to deforestation find their way into the river each day.