Megacities fast growing

HEALTH issues facing so-called 'megacities' like Tokyo, Mumbai or New York are poised to become a huge challenge for global policy as the cities grow, experts at the World Health Summit said.

Megacities, roughly defined as cities with a population of more than 10 million, are springing up around the world as people increasingly migrate from the fields to massive, sprawling urban centres.

There will be 27 of these megacities by 2020, up from 19 in 2007, said Victor Rodwin, director of the World Cities Project at New York University, with most located in Asia, South America or Africa.

Moreover, the cities themselves are growing at a ferocious rate. 'For every minute that I speak, a new person is going to be moving into Lagos, Kinshasa or Dhaka,' said Ricky Burdett from the London School of Economics.

One in every 25 people on the planet will be living in a megacity by 2025, predicted Francisco Armada Perez, an official from the World Health Organisation.

Health issues found elsewhere are exacerbated in megacities. Diseases such as AIDS, SARS or H5N1 bird flu can spread like wildfire, especially through slums, where one-third of urban dwellers live. Overcrowding and poor sanitation foster tuberculosis, another major challenge facing health officials in megacities.