UPSC 2014 CDS I GK Paper

Difference of duration of day and night is least near the Equator and progressively increases away from it. Lengths of days and nights in the poles vary so greatly that they have a 6-month day (during summers) and a 6-month night (during winters). On the other hand, the equator has a fixed 12-hour day and night, and their lengths are not influenced by seasons. This is due to the fact that the Earth's axis is tilted.