Odisha Chief Minister Naveen Patnaik on Tuesday launched the 'Green Mahanadi Mission', a plantation drive under which 2 crore saplings will be planted along the Mahanadi river and its tributaries.The Chief Minister launched the campaign during his visit to Boudh and Subarnapur districts where he planted a sapling on the bank of the Mahanadi.A massive plantation drive will be undertaken along the Mahanadi, Ib and Tel rivers. Two crore trees will be planted along the rivers in the state, said an official.The plantation drive will be carried out in 16,500 hectare and 500 km, the official said.Forest and Environment Minister Bijoyshree Routray said the aim of this programme is to protect the Mahanadi and keep it alive."Mahanadi's water is decreasing. If trees will be planted along its bank, the roots will store water. Following this, water level will increase as well as the river will store water," said Routray.