People walk through the Helden Tor (Hero's Gate) near the Homburg Palace in Vienna, Austria on Tuesday. (Photo: AFP)

The Austrian capital has retained its ranking as the world's most livable city, according to an annual report from the Economist.

Vienna once again came ahead of Melbourne, Australia－which had held the top ranking for seven years until losing it to Vienna in 2018－according to a report from the Economist Intelligence Unit, or EIU, released on Wednesday.

The top two were followed by Sydney, Australia; Osaka, Japan; and Calgary, Canada.

Each year, the EIU gives 140 cities scores out of 100 on a range of factors such as living standards, crime, transport infrastructure, access to education and healthcare, as well as political and economic stability.

Vienna－known for its convenient public transport, refreshing Alpine tap water and varied cultural life－scored 99.1 points out of 100, as it did last year.

"Western Europe and North America continue to be the most livable regions in the world," the EIU said in a news release.

Europe claimed eight of the top 20 spots, with cities in Australia, Canada, Japan, and New Zealand making up the rest.

However, the City of Light, Paris, dropped six places to 25th due to this past year's anti-government yellow vest protests－images of which went around the world.

For the first time, the index noted the effects of climate change on livability, with New Delhi and Cairo plunging in the rankings to 118th and 125th place, respectively, due to "poor air quality, undesirable average temperatures and inadequate water provision".

"We expect problems relating to climate change to put increasing pressure on livability scores in the coming years and for the number of cities affected to grow," Agathe Demarais of the EIU said.

Improvements in livability that had taken place in cities of emerging markets in recent years－thanks to greater stability as well as better education and healthcare－"are under serious threat from an increasingly adverse climate", she said.

London and New York rank 48th and 58th, respectively, as they continue to struggle under the perceptions of the risk of crime and terrorism and overstretched infrastructure.

The least livable cities were Karachi, Pakistan; Tripoli, Libya; Dhaka, Bangladesh; Lagos, Nigeria; and, at the very bottom, Damascus, Syria.

Vienna, for the tenth time, also won top place in another survey this year, the annual quality of living index by human resources consulting firm Mercer.