What are the features of India's first manned submersible Matsya 6000?

India's first manned submersible Matsya 6000, capable of taking three personnel to 6,000 metres underwater, is being prepared for deep sea exploration missions. The spherical vessel has a 2.1 metre diametre and an endurance of 12 hours under normal operation. It's built from an 80 mm-thick titanium alloy, enabling it to withstand extreme pressures underwater.