OSLO - Oslo, London and Amsterdam are leading a shift by major cities to eliminate greenhouse gas emissions from transport, helped by new technologies that will curb climate change and reduce air pollution, a study showed on Tuesday (April 25), reported Reuters.

Singapore came in at 13th in the ranking of 35 cities by the independent London-based Centre for Economics and Business Research (CEBR), sponsored by smartphone chip maker Qualcomm.

The CEBR report gauges both existing policies and plans to promote greener transport with everything from electric cars to bicycles.

It said Singapore, known as the Garden City, lives up to its name "as green space covers almost 50 per cent of the city.. However, Singapore scores modestly on many other status quo indicators, ranking near the middle for CO2 emissions and energy efficiency".

The report described Singapore as "perhaps the most exciting city on the index" in terms of technology.

"While other cities wait for autonomous cars to become available, Singapore-based firm nuTonomy has already put driverless taxis on the roads. Currently trialling a small fleet of electric, autonomous vehicles, the company aims to make Singapore the first country with a national driverless-taxi service by 2018. The government is also conducting trials with driverless electric buses," it said.

European cities filled eight of the top 10 spots, along with Tokyo and Seoul.

"Oslo is set to be the world's first city with a zero emissions transportation solution," the report said.

The Norwegian capital's metro, trams and buses already run largely on hydro-electricity and Norway has the highest percentage of electric cars of any nation. The Oslo council also plans to sharply restrict cars to its city centre.

The report said second-placed London "may not seem an example of a green city to all residents" but most rely on public transport, rather than cars, and are among the most energy efficient urban dwellers in the world.

"London is somewhat unfairly considered a smoggy, dark city," CEBR managing economist Nina Skero told Reuters.

London also wants to cut greenhouse gas emissions by 60 per cent from 1990 levels by 2025 and has promoted electric cars and bike-sharing, it said.

Amsterdam, in third, has done more than almost any other city to promote cycling and to cut emissions, it said.

CEBR's index included city air pollution as one of 20 factors along with others such as city carbon emissions, levels of congestion, public investments in infrastructure, green spaces, charging points for electric vehicles, incentives for green travel and city commitments to low emissions.

Other Asian cities in the top 20 are Hong Kong, which ranked 16th, and Beijing, 20th.

Cairo was the bottom of the list of 35 cities, just below Nairobi, Mumbai and Istanbul, reflecting population growth and a focus on ending poverty that often means burning more gasoline.

Ms Skero said a city with completely emissions-free transport was probably at least 15 or 20 years away and that Oslo could well be overtaken.

Many cities have set more ambitious goals for restricting emissions than national governments after nearly 200 countries reached a climate agreement in Paris in 2015 to shift the world economy away from fossil fuels.

US President Donald Trump, who doubts that man-made global warming has a human cause, is considering whether to pull out of the Paris Agreement.

San Francisco, in 14th, was the top-ranked city in the United States, where heavy reliance on cars rather than public transport limits options for cities to introduce radical goals to phase out emissions, the study said.