Karachi is the capital of the Pakistani province of Sindh. It is the largest city in Pakistan, and seventh largest city proper in the world. Ranked as a beta-global city, the city is Pakistan's premier industrial and financial centre, with an estimated GDP of $164 billion (PPP) as of 2019. It is also Pakistan's cultural, educational, and political hub. Karachi is Pakistan's most cosmopolitan city, its most linguistically, ethnically, and religiously diverse city, as well as one of Pakistan's most secular and socially liberal cities. With its location on the Arabian Sea, Karachi serves as a transport hub, and is home to Pakistan's two largest seaports, the Port of Karachi and Port Bin Qasim, as well as Pakistan's busiest airport, Jinnah International Airport.