Mumbai floods
Idian commuters walk through floodwaters past stranded motor vehicles after heavy torrential rains paralysed the city of Mumbai in July 2005. SEBASTIAN D'SOUZA/AFP/Getty Images

At least 40 million Indians are expected to be at risk from rising sea levels by 2050, with the cities of Mumbai and Kolkata being hit the hardest. A United Nations report has warned that seven of the 10 most vulnerable countries in the world are in the Asia Pacific region, with India topping the chart.

The Global Environmental Outlook (GEO-6) noted that the worst impacts of climate change will be seen in south-east Asia. After India, Bangladesh is expected to be effected the most with 25 million people at risk, followed by China at 20 million people and then the Philippines with nearly 15 million.

According to the Press Trust of India, treport stated: "Some countries, such as China, India and Thailand, are projected to face increased future exposures to extremes, especially in highly urbanized areas, as a result of rapid urbanisation and economic growth."

The research also listed that Mumbai and Kolkata have the largest population that will be exposed to coastal flooding in India. Meanwhile, Guangzhou and Shanghai in China, Dhaka in Bangladesh, Yangon in Myanmar, Bangkong in Thailand, and Ho Chi Minh City in Vietnam are also on alert.

Although many associate the effects of climate change with rural areas, the UN has noted that growing urban settlements in coastal areas have affected the ability of coastal systems to respond to extreme climate events, therefore, putting them at greater risk of flooding in the years to come. Changes in settlement patterns, urbanisation, as well as socio-economic status have also contributed to making these cities more vulnerable.

The report stated: "Many of these cities are already exposed to coastal flooding, but have limited capacity to adapt due to their fixed location."

While urban areas are becoming increasingly affected by climate change, the research also warned that coastal areas exposed to cyclones and typhoons tend to negatively impact the poor more due to the fact that they live on hazardous land. The warning comes as Cyclone Roanu caused serious flooding in parts of India, Bangladesh, Myanmar and Sri Lanka.

The UN report has been published ahead of the UN Environment Assembly that is taking place in Nairobi, Kenya from 23 to 27 May. The conference will focus on the 2030 Agenda for Sustainable Development and aims to address critical environmental challenges facing the worldwide population.