Why is Iran's Chabahar Port important to India as US threatens its control over it?

The US' sanctions and threats of attacking Iran threaten India's control over Iran's Chabahar Port, in which India has invested ₹4,500 crore so far. Chabahar is 550 nautical miles from Gujarat's Kandla port and gives India easy access to Afghanistan, Central Asia and Europe while bypassing Pakistan. The port is also part of the 7,200-km-long International North-South Transport Corridor.