In South-East Asia Bangkok, Manila and Ho Chi Minh City are all low-lying urban areas, yet like Jakarta they have all taken too long to react to the threat of increased flooding.

ECONOMIST: The threat grows from rising water and sinking buildings

At least seven others (Chennai, Bangalore, Bogota, Ho Chi Minh City, Dongguan, Chengdu and Hyderabad) are now above 8 million, making it likely they could reach megacity status by 2030.

FORBES: The World's Fastest-Growing Megacities