Is Polkadot layer 1 or 0?

Excuse me, I'm a bit confused about the classification of Polkadot. Could you clarify whether Polkadot is considered a layer 1 or layer 0 blockchain? I've heard differing opinions on this matter and I'm trying to get a definitive answer. Layer 1 blockchains are those that have their own independent blockchain and consensus mechanism, while layer 0 blockchains are those that serve as the foundation for multiple blockchains to connect and interact. Given Polkadot's unique architecture and its ability to connect multiple blockchains, I'm not sure how to categorize it. Could you please elaborate on this point? Thank you for your time and assistance.