We consider Greenwich time while calculating the time for various places in the world because the Prime Meridian or the 0° longitude passes through Greenwich.
<u>Explanation:</u>
The 0° longitude marks the first meridian that the Sun passes over from. It acts as the line of reference for the world countries to set their times in accordance with it.
The Greenwich mean time was established in 1952 and it is since then that all the world countries have been following it.
