Sindhi biryani is served in nearly all the flights of an airline whose main hub is what?
Sindhi biryani: Sindhi biryani (Sindhi: سنڌي برياني‎ ) is a special meat and rice biryani dish originating from the Sindh province of Pakistan. Pakistan International Airlines: Pakistan International Airlines (Urdu: ‎ ) commonly known as PIA (Urdu: ‎ ) is the national flag carrier of Pakistan. Pakistan International Airlines:  Its main hub is Karachi while Lahore and Islamabad are its secondary hubs.
Karachi