Chiang Mai ranked 7th most polluted city in the world

The northern Thai city of Chiang Mai was ranked as the seventh most polluted in the world on Tuesday, according to air-quality monitoring website IQAir.

Chiang Mai registered an air quality index (AQI) of 170 on Tuesday. The scale has six categories: 0-50 (good air quality), 51-100 (intermediate), 101-150 (unhealthy for some groups), 151-200 (unhealthy), 201-300 (very unhealthy), and over 301 (hazardous).

The 10 cities with the worst air pollution in the world as of 10.30am according to IQAir were:

1. Delhi, India – 308

2. Dakar, Senegal – 232

3. Lahore, Pakistan – 191

4. Hanoi, Vietnam – 186

5. Dhaka, Bangladesh – 181

6. Kathmandu, Nepal – 180

7. Chiang Mai, Thailand – 170

8. Incheon, South Korea – 164

9. Seoul, South Korea – 164

10. Yangon, Myanmar – 159

Thailand’s capital, Bangkok, was in 16th place with an AQI of 134 on Tuesday.

IQAir also listed top 10 areas in Thailand with worst air quality on Tuesday morning, as follows:

1. Phetchabun province – 189

2. Khon Kaen province – 183

3. Chiang Rai province – 181

4. Udon Thani province – 180

5. Mae Mo district, Lampang province – 179

6. Muang district, Chiang Mai province – 170

7. Nakhon Ratchasima province – 166

8. Hua Hin district, Prachuap Khiri Khan province – 165

9. Hang Dong district, Chiang Mai province – 163

10. Samut Songkhram province – 161

AQI measures six types of air pollutants, namely PM2.5 (fine particulate matter with a diameter of 2.5 micrometres or less), PM10, ozone, carbon monoxide, nitrogen dioxide, and sulphur dioxide.