We use DURING to say when something happens. We use FOR to say how long something continues; e.g.

a) We went to Mumbai during the winter.
b) It rained during the night for three hours.
c) The first world war took place during 1914 and 1918.
d) Dr Jain will be here during Thursday and Friday.
e) I had to stay at hospital for five weeks.
f) I fell ill for a couple of days, but was fine after that.

For more chapters/topics on English Grammar read the following book authored by me.

Link for buying the above book

For English Practice Sets on various topics read the following book authored by me.

Link for buying the above book