Seven mega cities by 2030; Delhi most populous

As of now, India can boast of having five mega cities, Delhi, Mumbai, Kolkata, Bengaluru and Chennai, having a joint population of over 10 million people; however, by 2030, two more cities (Hyderabad and Ahmedabad) would cross the mark, taking the total number to seven.

Delhi, like now, will continue to be the second most populous city in the world till 2030, and would have added a whopping 9.6 million people by then.

The above facts have been stated in the 2016 World Cities Report, which was issued by the UN's department of economic and social affairs.

The report used the concept of "urban agglomeration," the contiguous urban or built-up area. For example, when they studied Delhi, its urban agglomeration included the satellite cities of Ghaziabad, Noida, Faridabad and Gurgaon, given that people in these nearby areas are economically and socially integrated with the main city.

Around the world, there are 31 such mega cities, housing about 500 million people, roughly 6.8% of the world's population. As per the report, by 2030, there would be 10 more mega cities, with a combined population of about 730 million.

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