A "white elephant" is used to describe something that is useless to you, but at the same time it costs a lot of money or effort to have around, and you can't ignore it. I think it came from an old story about an Indian prince who had a white elephant that he couldn't put to work (not sure why), but he still had to feed it a lot of food. And because it was an elephant, it was difficult to ignore. ;) A "white elephant sale" is another name for a junk sale where people could sell off the things they don't need anymore.

If you want a classic example of a "white elephant", see the Ryugyong Hotel, Pyongyang, North Korea.

it's a kind of brands of instant noodles in china

The white elephant in the room is an English idiom for a question that very obviously stands, but for the convenience of a person/persons it is ignored. If a white elephant were in the room it would be very obvious and very unlikely that anyone would be talking about it, hence the metaphor of the "white elephant".

White elephants used to describe country who has an elephant in her brand,i think another name for thailand or birma