Why there is no or why is there no?
There are no has to be followed by a plural. There is no has to be followed by a singular. There is no is used with uncountable nouns too, of course, because they are always singular.
Why is there or why there is?
Senior Member. The second sentence is incorrect... unless it is not being used as a question. For instance: "I'm talking about why there is no Nobel Prize in mathematics." But if you want to ask a question, you have to use "Why is there... ?"