SINGAPORE -- Southeast Asian bond issuers, both private and public, are putting greater investment on environmental, social and governance standards to reach a bigger pool of global investors.

To encourage this growth, the Association of Southeast Asian Nations adopted new region-wide guidelines on Oct. 11 aimed at ensuring transparency to investors.

Thailand's Kasikornbank this month issued a $100 million sustainability bond, a type of borrowing used to finance projects that bring environmental and social welfare benefits. It was offered through the bank's Hong Kong branch to foreign investors.

The country's second-largest lender cited its efforts aimed at "supporting the development of Thai and regional capital markets" and "driving sustainable growth of Thailand and global communities."

Singaporean company Impact Investment Exchange, or IIX, set up its second social bond program aiming to empower Asian women. IIX, a platform that connects social enterprises and investors, partnered with top Singaporean lender DBS Group Holdings last month to launch the Women's Livelihood Bond Program, a series of bonds targeting a total of $100 million.

The environmental, social and sustainability themes are close to the heart of people in Southeast Asia, a region prone to natural disasters associated with climate change. Social issues such as poverty and inaccessibility to basic infrastructure are serious problems.

For bond issuers, tapping into so-called ESG investing -- which uses environmental, social and governance criteria -- can lead to wider range of investors, including big pension funds and other institutional buyers.

"There is a benefit in getting a broader investor base," said Mikkel Bilyk Larsen, chief sustainability officer for DBS. The bank itself issued $500 million in green bonds in July 2017.

Sustainability and social bonds are a newer but growing segment of ESG investment.

A report by the nonprofit Climate Bonds Initiative says $155.5 billion was raised in the green bond market globally last year, up 78% increase from 2016. Growth continued this year, though at a slower pace of 4% on the year for the first half of 2018, the organization reported.

The global push to mitigate climate change drives the interest among issuers and investors. Asian green bond issuance accounted for 36% of global volume, up from less than 10% in 2015. Much of the growth in Asia has been fueled by China, but Southeast Asian countries are gaining momentum.

The sovereign market is following suit. In February, Indonesia issued a $1.25 billion green sukuk Islamic bond, the first of its kind in the world. Indonesia, the world's largest coal exporter and the fifth-biggest emitter of greenhouse gases, hopes to boost its emission-reduction commitment with this issuance.

Yet green bonds remain less than 1% of the total bond market worldwide, and the percentage is even lower in Asia, said Herry Cho, ING's Asia Pacific head of sustainable finance. This indicates potential for further growth, she said.

To accelerate the nascent market, the Association of Southeast Asian Nations announced a new standard for social and sustainability bonds at the ASEAN Capital Markets Forum conference on Oct. 11.

ASEAN based its version on the standard set by the International Capital Market Association, but strengthened some aspects such as ensuring investor access to information on the use of proceeds.

"[Standardization] provides certainty to investors that bonds with such labels have met acceptable criteria in the use of proceeds, process for project evaluation and selection, management of proceeds and reporting," Lee Boon Ngiap, the Monetary Authority of Singapore's assistant managing director, said at the conference.

ASEAN announced a standard for green bonds a year ago. This version uniquely excludes fossil fuel power generation projects -- so coal power generation, widely accepted in China as a green project, will not pass the standard in Southeast Asia.