Most of the Ganga River water in the Uttar Pradesh-West Bengal stretch is unfit for drinking and bathing, a map released by the Central Pollution Control Board (CPCB) has indicated.
The National Green Tribunal last month directed the National Mission for Clean Ganga (NMCG) to install display boards at a gap of 100 km to indicate whether the water was fit for bathing or drinking.
It also asked the NMCG and the CPCB to upload on their website, within two weeks, a prominent map showing where the water was good for bathing and drinking on the river.
In compliance with the National Green Tribunal's direction, the CPCB uploaded the map which showed most of the length of the Ganga river dotted in red.
Other than stretches in Uttarakhand and a couple of places as the river enters Uttar Pradesh that are marked in green (fit), the river is unfit the whole way till it drains into the Bay of Bengal in West Bengal barring one spot at the border of UP and Bihar of Arrah.
Water activist Manoj Misra said coliform levels indicate the presence of dangerous bacteria in the water and if it is below 500 then only it could be suitable for drinking by boiling.
The coliform level showed in the map is 10 times the permissable limit for drinking at 5000, he said.
"Most of the stretch of Ganga is not suitable for drinking and bathing as it has been shown in the map," he said.
The map 'Sustainability of River Ganga Water' on the website uses the criteria of dissolved oxygen (more than 6 mg/litre), bio-chemical oxygen demand (less than 2 mg/litre), total coliform levels (5000 most probably number per 100 ml) and pH (range between 6.5 to 8.5) to assess the health of the river.
The 2,525 km river rises in the western Himalayas in Uttarakhand, and flows south and east through the Gangetic Plain of North India.
After entering West Bengal, it divides into two rivers: the Hooghly River and the Padma River. The Hooghly flows through several districts of West Bengal and into the Bay of Bengal near Sagar Island.