Is it a family gathering or friends circle?

Family only here. In Australia, it was often a barbecue kind of thing with friends too. But here, it is pretty strict.

usually go out for picnic either on Christmas day or new year day. Everyone contribute in their own way.

This sounds like a great day. I wish there was more of this culture here. I get it for Christmas though, as it is definitely an indoor event, but it doesn't even happen in the summer here.