Why alot of my bollywood music which I downloaded is getting unavailable on apple music?

Check out this article: Get help with iCloud Music Library

If some of your songs are missing or the song names appear in gray text

If songs that you bought are missing or the song names appear in gray text, they might use digital rights management (DRM). You need to authorize your computer before you can play these songs.

After you authorize, choose File > Library > Update iCloud Music Library from the menu bar at the top of your computer screen or the top of the iTunes window.

If you synced the songs that appear with gray text to your iOS device from a Mac or PC, turn on iCloud Music Library on that computer and your library should update.

If that doesn't work, you can delete and re-add the songs to your library: Delete songs and videos from your iCloud Music Library

On your iPhone, iPad, or iPod touch

Open the Music app and tap Library. Find the song, album, playlist, TV show, or movie that you want to delete, then use 3D Touch or long press the item.

Depending on if you have the item downloaded to your device, you'll see one of these options:

• If you haven't downloaded the item to your device, tap "Delete from Library" to delete the item from iCloud Music Library.
• If the item is downloaded to your device, tap Remove. Then tap Remove Downloads to remove the item only from your device, or tap "Delete from Library" to delete the item from iCloud Music Library.

If you want to see only content that you downloaded to your device, follow these steps:

Tap Library > Downloaded Music. A message that says "Showing only music on this [device]" appears at the top of the screen. Tap Library in the upper-left corner to go back to your full library.