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Asian Development Bank

100 Climate Actions from Cities in Asia and the Pacific


The Government of Thailand is addressing the congestion woes of its capital city by almost doubling the Mass Rapid Transit lines running through the city with new pink and yellow lines.

Adding to the five existing Mass Rapid Transit (MRT) lines currently operating in Thailand’s capital, the creation of the new Pink and Yellow lines will expand the options for travellers looking to escape the congested roads.


Planned for completion by the end of 2021, the new lines will expand the 100 km of existing routes to 164.5 km, with more planned for the future.

Bangkok has been reducing the amount of congestion on its roads, but it still ranks as the 11th most congested city in the world, according to navigation company TomTom’s congestion index. With MRT only accounting for 4% of all journeys in the city, the transportation sector is responsible for a significant proportion of greenhouse gas emissions and also contributes heavily to the often hazardous air quality.

The city hopes that the expansion of the MRT will encourage more people to switch from car to public transport, reducing CO₂ equivalent emissions by an estimated 45,000 tons annually by 2025 and improving air quality for citizens.

ADB provided financing of over $316 million for the project.

The new lines will further encourage residents to take public transportation over private (photo by ADB).

The Challenge

Bangkok is one of the most congested cities in the world due to the congestion of its roads. By continuing to improve its MRT system, residents will continue to prioritize public transport over private.


Health Through the continued use of public transport, the health of residents will be improved given a reduction in the amount of harmful NOx particles in the air.

Social The new lines will follow a universal design which will encourage use for all residents, including women, children, the elderly and disabled people.

Economic The city believes the two new lines will generate 2,000 jobs.