Karachi is the largest and most populous city in Pakistan. The population of Karachi is estimated to be 24 million in 2015. The population and demographic distribution in the megacity has undergone numerous changes over the past 150 years. On 14 August 1947, when it became the capital city of Pakistan, its population was about 450,000 inhabitants and was capital of Sindh province. However, the population rapidly grew with large influx of Muslim refugees after independence in 1947. By 1951, the city population had crossed one million mark. in the following decade, the rate of growth of Karachi was over 80 percent. Today, the city has grown 60 times its size in 1947 when it became the country's first capital. Although, Islamabad remains the nation's capital since the 1960s, the city's population continues to grow at about 5% per annum, largely thanks to its strong economic base.
A person from Karachi is known as a Karachiite.
Whereas most megacities in the developing world have grown out of rural-urban migration from the countryside not too distant from them, Karachi's demographics are the largely contributed by long-distance immigration. Before the independence of Pakistan, Karachi already had a diverse mix of religions and ethnic groups. After the independence, most of the Urdu speaking Muslim refugees of the partition of India settled in Karachi. Likewise, a large number of Hindus left the city in 1947 due to Hindu-Muslim riots and settled in India. Predominantly Urdu speaking Muslim refugees known as Muhajirs formed the dominant ethnic group in Karachi. Muhajirs originated from different parts of India and brought with them their local cultures and cuisines, thus further adding to the already diverse mix of people that earlier inhabited Karachi. Currently, these older groups of people and continuing migration from different parts of Pakistan have contributed to a rich and diverse mix of people that live in Karachi. This has further been diversified with migration from other non-traditional countries such as by Arabs, people from different Middle Eastern countries, as well as Afghans and more recently from the Central Asian Republics. The city is also home to Pakistan's largest Jewish, Nestorian and Armenian communities. This has given the city a very metropolitan character, and has earned it the title as the melting pot of Pakistan.