This research about PM 2.5 pollution is one of the Thai environmental problems that still needs to be fixed, even though it has not recovered much since 2019. The Thai government has an answer to this crisis that has affected people, which is short-term and long-term solutions for people and other organizations to apply. However, it requires time to operate, it is not effective enough, making many people in many areas still face with this problem. This qualitative study explores the number of PM2.5 that happened in Thailand from 2019 to 2023, the cause of PM2.5, and the policies of PM2.5 and analyzes existing policies used in the country with indicators from global organizations. The secondary data was collected from Chulalongkorn University, IQAir from 2020 to 2023, a case study from Beijing, and a case study from Seoul, including UN SDG for analysis. From the information we have found, the causes of PM 2.5 in Thailand come from man-made and environmental such as seasonal, climate change, and burning crops, including the area that gets impacted the most is in northern Thailand such as Chaing Mai. This research shows people’s actions and the environment clarify the impact in Thailand and suggests a solution for decreasing PM 2.5 in Thailand.