STATUS, TRENDS, AND PRIORITYINTERVENTIONS ACROSS EIGHT ASEAN CITIES MARCH 2026 AIR QUALITY INSOUTHEAST ASIA STATUS, TRENDS, AND PRIORITY INTERVENTIONSACROSS EIGHT ASEAN CITIES MARCH 2026 Creative Commons Attribution 3.0 IGO license (CC BY 3.0 IGO) © 2026 Asian Development Bank6 ADB Avenue, Mandaluyong City, 1550 Metro Manila, PhilippinesTel +63 2 8632 4444; Fax +63 2 8636 2444www.adb.org Some rights reserved. Published in 2026. ISBN 978-92-9277-748-7 (print); 978-92-9277-749-4 (PDF); 978-92-9277-750-0 (ebook)Publication Stock No. TCS260121-2DOI: http://dx.doi.org/10.22617/TCS260121-2 The views expressed in this publication are those of the authors and do not necessarily reflect the views and policiesof the Asian Development Bank (ADB) or its Board of Governors or the governments they represent. ADB does not guarantee the accuracy of the data included in this publication and accepts no responsibility for anyconsequence of their use. The mention of specific companies or products of manufacturers does not imply that theyare endorsed or recommended by ADB in preference to others of a similar nature that are not mentioned. By making any designation of or reference to a particular territory or geographic area in this document, ADB does notintend to make any judgments as to the legal or other status of any territory or area. This publication is available under the Creative Commons Attribution 3.0 IGO license (CC BY 3.0 IGO)https://creativecommons.org/licenses/by/3.0/igo/. By using the content of this publication, you agree to be boundby the terms of this license. For attribution, translations, adaptations, and permissions, please read the provisionsand terms of use at https://www.adb.org/terms-use#openaccess. This CC license does not apply to non-ADB copyright materials in this publication. If the material is attributedto another source, please contact the copyright owner or publisher of that source for permission to reproduce it.ADB cannot be held liable for any claims that arise as a result of your use of the material. Please contact pubsmarketing@adb.org if you have questions or comments with respect to content, or if you wishto obtain copyright permission for your intended use that does not fall within these terms, or for permission to usethe ADB logo. Corrigenda to ADB publications may be found at http://www.adb.org/publications/corrigenda. Notes: In this publication, “CNY” refers to the Chinese yuan and “$” refers to United States dollars, unless otherwise stated.ADB recognizes “China” as the People’s Republic of China, “Korea” as the Republic of Korea, “Vietnam” as Viet Nam,and “Hanoi” as Ha Noi. On the cover:Aerial view of Manila, Philippines; an electric bus on the road in Ha Noi; a windmill farm in Viet Nam; anda recycling facility in Indonesia (photos by ADB). Tables, Figures, and BoxAcknowledgmentsAbbreviationsExecutive Summary v vii ix ASEAN in the Past DecadeASEAN Cities Relative to the WHO Air Quality GuidelinesAir Quality in ASEAN’s Largest Cities 2Air Quality Monitoring Capacity and Gaps9 Population-Based Monitoring AdequacyDeterminants of Monitoring Network SizeMonitoring Coverage by PollutantData Accessibility Laws, Plans, and StrategiesSubnational Implementation and Local ActionAlignment with Climate CommitmentsAmbient Air Quality Standards in ASEANAir Quality in Public Health ManagementSectoral InterventionsPublic Reporting 5Financing Clean Air Action6City-Level Assessment and Priority ActionsPath Ahead for ASEAN Cities Appendixes 1Methodology Scope and Limitations of the ReportData Availability and AccessibilityData CollectionData Processing and Quality Assurance 2Case Studies BangkokBogorHa NoiHo Chi Minh CityIloilo CityJakartaPhnom PenhQuezon City Tables 1Prescribed Sampling Points from the European Union Directive 2008/50/EC102Government-Owned vs. Recommended Monitoring Sites in ASEAN Countries113National Air Quality Policies and Plans in ASEAN Countries194Subnational Air Quality Policies and Plans in ASEAN Countries215National Ambient Air Quality Standards in ASEAN Countries256E-Mobility Targets in Indonesia277E-Mobility Targets in Malaysia278E-Mobility Targets in the Philippines279E-Mobility Targets in Singapore2810E-Mobility Targets in Thailand2811E-Mobility Targets in Viet Nam2812Nationally Determined Contributions and National Policies and Strategies Related to32Coal Use in ASEAN Countries Figures 1Annual PM2.5Levels in ASEAN Cities, 2014-202412Annual PM10Levels in ASEAN Cities, 2014-202423Distribution of ASEAN Cities by 2024 PM2.5Levels Across WHO AQG and Interim Targets34Distribution of ASEAN Cities by 2024 PM2.5Levels Across WHO AQG and Interim Targets, by Country35Distribution of ASEAN Cities by 2024 PM10Levels Across WHO AQG and Interim Targets46Distribution of ASEAN Cities by 2024 PM10Levels Across WHO AQG and Interim Targets, by Country57Distribution of ASEAN Cities by 2024 NO2Average Across WHO AQG and Interim Targets68Distribution of ASEAN