"यह ज़रूरी नहीं है।"
अनुवाद:It is not necessary.
In English necessary is not the same as compulsory or as important, although they are all similar.
"Necessary" means "needed". Oxygen is necessary for life. It is not necessary to give me a birthday gift. Flour is necessary for making bread.
"Compulsory" means that you MUST do something - there could be a law that forces you to do this. It is compulsory to wear seatbelts. It is not compulsory to wear sunscreen, but it is a good idea. It is compulsory to vote in Australia.
"Important" means valuable or significant. It is important to remember your anniversary. It is not important to be popular. It is important to have travel insurance.