To answer this question, let's analyze each statement individually:

Statement 1: The Ganges river dolphin can only live in freshwater and is essentially blind.

The Ganges river dolphin, scientifically known as Platanista gangetica, is a freshwater dolphin species found primarily in the Ganges and Brahmaputra river systems in India, Nepal, and Bangladesh. This species is indeed restricted to freshwater environments and cannot survive in saltwater or marine habitats. It is well adapted to the riverine ecosystem, with physical characteristics such as a long and slender body, a long beak, and a flexible neck that allows it to navigate through the shallow and turbid waters.

Additionally, the statement correctly states that the Ganges river dolphin is essentially blind. This species has small, non-functional eyes and lacks a lens, which makes it almost completely blind. However, it compensates for its lack of vision by using echolocation, a process in which it emits sounds and listens to the echoes to navigate and locate prey in the river.

Therefore, statement 1 is correct.

Statement 2: In India, their population is present only in the Upper Ganga River.

This statement is also correct. In India, the Ganges river dolphin population is primarily concentrated in the Upper Ganga River, which refers to the stretch of the Ganges River located in the northern part of the country. This region includes states such as Uttarakhand, Uttar Pradesh, and Bihar. The dolphins are most commonly found in deep pools and rapids of the river, where they can find suitable habitat and prey.

It is important to note that while the Ganges river dolphin population is primarily concentrated in the Upper Ganga River, there have been occasional sightings of this species in other parts of the Ganges River system, such as the middle and lower stretches. However, their presence in these areas is relatively rare compared to their stronghold in the Upper Ganga River.

Therefore, statement 2 is also correct.

In conclusion, both statements 1 and 2 are correct. The Ganges river dolphin can only live in freshwater and is essentially blind, and in India, their population is present primarily in the Upper Ganga River.