Karachi is the largest city, main seaport and financial centre of Pakistan, as well as the capital of the province of Sindh. The city has an estimated population of 21 million people as of April 2012. At a density of nearly 6,000 people per square kilometre (15,500 per square mile) Karachi is the most populous city in the country, the world's 3rd largest city in terms of population by city proper and also the 11th largest urban agglomeration in the world. It is Pakistan's centre of banking, industry, economic activity and trade and is home to Pakistan's largest corporations, including those involved in textiles, shipping, automotive industry, entertainment, the arts, fashion, advertising, publishing, software development and medical research. The city is a hub of higher education in South Asia and the Muslim world. Karachi is ranked as a Beta world city.
Contributions by Hirnee cheema, Swerveut, and Aalahazrat.