Kolkota (West Bengal): The Hooghly or Kati-Ganga flows south for about 260 km into the Bay of Bengal, through a heavy industrialised area with more than half of West Bengal's population.
Household wastewater and industrial effluents flowing directly into the river are the major causes of its pollution.
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Tolly Nullah, a British-era canal, discharges a large quantity of sewage waste into the river.
Under the pollution abatement and rehabilitation works, three sewage treatment plants will be set up with funds from the Namami Gange to stop the flow of sewage from Tolly Nullah into the Hooghly.
Rajiv Ranjan Mishra, Director General of National Mission for Clean Ganga said, "It has been converted into a big nullah. At one point it was called Adi Ganga. So, it was the king of the river. But, it has degenerated over a period of time. We have some problems with that project. 26 MLD STP we want to construct and then intercept this sewage to that STP and clean it up. We have sanctioned the project and the state is calling up tender".
He added, "There are certain issues of encroachment and people settling along that nullah, so I think all these things are taken care up by the state and local authorities and we will ground this project".
A few kilometers from Kolkota is Barrackpur, the site of the first cantonment of British East India Company.
Located on the banks of Hooghly, Barrackpur is now a densely populated city. It lacks sewage treatment plants, and consequently, its wastewater flows directly into the river.