You can read updates on Cryptopia's Twitter account & on Cryptopia's site under News/Information Section.
When you look a little closer you'll see that the closure of the LTC Base Market is temporary. Cryptopia is working on a solution and creating a sister site for LTC markets.
Here's the post published by one of the founders of Cryptopia: Hex @ 1/11/2018 12:11:38 AM
Further Updates On LTC Basemarkets
I understand that while this may not be the update many people want to hear, it at least will hopefully provide everyone with a clear understanding of the path forward.
Cryptopia will be standing up new sister sites such as ltc.cryptopia.co.nz to handle base markets dedicated to LTC on their own trade engine and database to allow them to continue to trade, and allowing cryptopia.co.nz to resume registrations.
You will still need to transfer funds between the different sites to trade on each of them but this will be able to be handled instantly by Cryptopia in the background with atomic swaps, so you'll still have the single Cryptopia account that you use on the different exchanges.
As such, we will be permanently closing the LTC basemarkets on cryptopia.co.nz
Users will have a month to cancel their open orders after which point the markets will be closed and your orders will be cancelled for you.
Further updates on the timeline for the new LTC exchange will be posted as they become available.