Hi @Pratyush, welcome to the community!
Spotify want all the make all the world’s music available, but availability can vary over time and between countries, depending on the permissions from rights holders.
Be sure that new content is added to Spotify every day, so if you can’t find something you’re looking for right now, it may appear soon, so please check back!
Meanwhile you can get in touch with Joji through his social media channels :)
Let me know if you have any other questions!