There are various reasons cited. Again, there's the decision not to import. Another is hoarding and price manipulation. There's also the fact that it's holiday season, although the price has already been rising for months. As a matter of fact, just 6 months ago, a kilo is only around $2. But of all the reasons cited, none is convincing enough.
This of course shouldn't be the reason but it would be for sure the cure!
To officially insist not to import even if the sufficiency level right at the source itself is 0% is absurd. That's an insensitive decision. Well, the rich leaders up there can't feel the shortage because they can have much of it regardless of the price.
Of course, importation would have to be balanced. Importing onions, which are much cheaper, could significantly affect local onion farmers. But at this time when even local producers have zero supply? When the price per kilo more than doubles the price of pork, beef, and whatever meat? This is simply ridiculous!
If memory serves me right, limiting importation during (or right before) harvest seasons to help out local farmers is one of the campaign platforms of the incumbent President.
There are some stores (Gov't Project) in the Metro called KADIWA that sells red and white onions for ~$3. Those came directly from the farmers and that's why they're cheaper. That's still a short-term solution and one politician (Pres. sister) claims that the farming system and the distribution methods needed to change. She's probably right about the farming system but I don't know about the distribution. From what I know, the farm-to-market roads have greatly improved the past few years.