If to talk about new year's day. It is a day that many people go together to celebrate. Some people go out to celebrate with the family, some people go out to celebrate with friends.
Talking about the new year. It is a day when many people are brought together to celebrate. Some went out to celebrate with family. Some went out to celebrate with friends.
If talking about new year's day. It's on a lot of people are celebrating. Some people go out and celebrate with family. Some people hang out with friends.