London, March. 28 (AP): A global study has identified India's low-lying coastal areas among other Asian nations vulnerable to global warming and sea-level rise. India along with Bangladesh, China, Vietnam and Indonesia are countries with five largest population living in threatened coastal areas, the study in the journal Environment and Urbanization said.

It has identified the world's low-lying coastal areas that are vulnerable to global warming and sea-level rise, and urged major global cities from New York to Tokyo to wake up to the risk of being swamped by flooding and intense storms if nothing is done.

Of the more than 180 countries with populations in the low-elevation coastal zone, about 70 percent have urban areas of more than 5 million people that extend into it, including Mumbai, Tokyo, New York, Shanghai, Jakarta and Dhaka. Asia is particularly vulnerable and in general poorer nations are most at risk, the peer-reviewed scientific study.

In all, 634 million people live within such areas - defined as less than 10 meters (33 feet) above sea level - and that number is growing, said the study released today.

It does not say exactly what should be done, but it warns that it won't be cheap and it may involve moving lots of people and building protective engineering structures. And, it adds, countries should consider halting or reducing population growth there.

"Migration away from the zone at risk will be necessary but costly and hard to implement, so coastal settlements will also need to be modified to protect residents," said study co-author Gordon McGranahan of the International Institute for Environment and Development in London.