WE KNOW THAT DOLPHINS ARE MARINE ANIMALS THEY ARE FOUND IN OCEANS AND SEAS.......... SO HOW IT IS WRITTEN IN (SCIENCE) "POLLUTION OF AIR WATER" THAT POLLUTION IN RIVER GANGA LEAD TO THE GRADUAL DECLINE OF THE DOLPHINS IN THE RIVER GANGES ?

well this are another type of dolphin named gangetic dolphin .They can be identify by their rostrum and visible teeth on the lower jaweven when their mouth is closed. They do not have eyes but understand what lies ahead and how far by hearing that sound created by then .It is called echolocation. Due to pollution gangs water they becominging exint nowadays