In its affidavit to the National Green Tribunal (NGT), Kolkata Port Trust (Syama Prasad Mookherjee Port) has countered the views expressed by green activist Subhas Datta on the possible causes behind the Indian Botanic Garden riverbank erosion.

Captain Abhijit Ghosh, Director of Port Marine Department, in the affidavit said there was no scientific correlation between dredging and the riverbank erosion. The port only dredged the navigation channel for the movement of vessels to and from Kidderpore Port, it was observed.

The affidavit affirmed that 4.7 sq km between the expanse of Shalimar to Kidderpore in the north and Metiabruz in the south, the water-carrying capacity over the last 20 years has remained the same.According to the affidavit, the port records affirmed that no dredging was carried out near the eroding bank. It said that dredging is carried out in the shallow region of the channel and dredged silt is carried to the nearest deep pocket where it is dumped. The depth of the channel and the deep pockets are regularly monitored by the port.

The affidavit claimed that the erosion along the west bank was caused by the propagation of strong tidal bore. During the equinoxes, when the moon exerts a strong pull on the earth, it causes significant damage to the bank. The desilting of the entire river was economically unviable. Thus, only navigable channels are dredged, it has been claimed.