Cryogenics is the science of materials at temperatures below negative 153 degrees C.
Cryogenics deals with thermal conditions in which even gases such as hydrogen, nitrogen are liquid.
Many cryogenic materials have desirable properties. For example, hydrogen is one of the best rocket fuels but it can only be used as a liquid, so it needs to be cryogenically cooled.
Cryogenic hydrogen and cryogenic oxygen power the third stage of ISRO’s Launch Vehicle Mark-3 rocket.
Magnetic resonance imaging (MRI) devices used in medical diagnostics use cryogenic fluids to cool their magnets.