Hypoxia types are:

1. Anaemic or hypaemic hypoxia: The oxygen normally mixes with haemoglobin in the blood and is transported to the body via the red blood cells. Anaemic hypoxia arises from a reduction in the functional haemoglobin in the blood (anaemia) or the inability of oxygen to combine with haemoglobin (carbon monoxide poisoning).

2. Stagnant hypoxia: Stagnant hypoxia occurs when the oxygen content of the blood is normal, but the delivery of oxygen to tissues is impaired due to inadequate blood flow or circulation. It can be caused due to extreme cold or excessive g-forces.

3. Histotoxic hypoxia: Histotoxic hypoxia is a type of hypoxia that occurs when the body's cells are unable to utilize the oxygen delivered to them, despite normal oxygen levels in the blood and adequate blood flow. It can be caused due to lack of vitamin B1 or poisoning (i.e. alcohol, cyanide).

4. Hypoxic hypoxia: Hypoxic hypoxia is caused due to the reduction of oxygen entering the blood due to low partial pressure of oxygen with altitude. It is caused when flying a depressurized aircraft at high altitudes.

Anaemic Hypoxia ⇒ due to haemoglobin reduction
Stagnant Hypoxia ⇒ due to reduced blood flow to the tissues
Histotoxic Hypoxia ⇒ due to inability of the body cells to utilize the oxygen
Hypoxic Hypoxia ⇒ due to low partial pressure of oxygen with altitude