Summary for 15–21 December 2025:

From 19–21 December, air quality was poor in Kurunegala, Colombo (Gregory’s Road), Mirihana, Battaramulla (CEA), Chilaw (CEA), Puttalam, Trincomalee, Jaffna, and Anuradhapura. Most locations recorded Unhealthy AQI values between 151 and 200, while some recorded Unhealthy for Sensitive Groups values between 101 and 150. These high pollution levels were caused by polluted air flowing from the northern parts of India through the Bay of Bengal.

Earlier in the week, from 15–18 December, air quality was better. During this time, AQI values mostly stayed between Good (0–50) and Unhealthy for Sensitive Groups (101–150). The main exception was Chilaw on 15 December, where the AQI reached 152, which is in the Unhealthy (151–200) range.

Looking at the whole week, average weekly AQI values were between Moderate (51–100) and Unhealthy for Sensitive Groups (101–150). Battaramulla (CEA) had the highest weekly average AQI at 124, while Digana had the lowest at 57.

Weekly Air Quality Index (AQI) Levels:

  • Moderate (AQI  51-100  ): Akurana-AV-Outdoor, Digana, Kurunegala, Ambalantota
  • Unhealthy for Sensitive Groups (AQI 101-150): Colombo Gregory’s Road, Mirihana(Cleanco), Battaramulla(CEA), Chilaw(CEA), Puttalam, Trincomalee, Jaffna, Anuradhapura
Weekly Air Quality in Selected Towns of Sri Lanka (15 – 21 December 2025)

Observed fine particulate measurements by the hour for the last week.

Air Quality impact on human health

 

Fine particulate matter (PM 2.5) are generally 2.5 microns and smaller in size. Such particles are inhalable and easily lodges inside the lungs reducing capacity. PM2.5 is a concern for people’s health when levels in the air are high. The levels of risk are shown in the dial shown against the US EPA air quality standards. AQ has a scale that run from 0-500, that tells you how clean or polluted your air is. Each level on the scale corresponds to a different level of health concern.

 

AIR QUALITY BASICS

Air pollution, a widely- talked and argued topic today has been a primary cause of unforeseen climatic changes, many health problems associated with respiratory diseases and ecosystem damage. Vehicular and industrial emissions, dust, burning of fossil fuels, open burning of garbage waste and natural phenomena such as volcanoes, wildfires and pollen contribute to air pollution. Polluted air consists of both particulate matter of fine dimensions and gaseous matter. The presence of these impurities decreases the pureness of the air we breathe.

 
AQI

United States Environmental Protection Agency (US EPA) has set up a standard to measure the level of air pollution by the following 5 major air pollutants:

  • Ground- level ozone (O3)
  • Particle pollution (PM2.5 and PM10)
  • Carbon monoxide (CO)
  • Sulphur dioxide (SO2)
  • Nitrogen dioxide (NO2)

Particulate matter of diameter less than 2.5 micrometers (PM2.5) and diameter less than 10 micrometers (PM10) and gases, ozone, carbon monoxide, sulphur dioxide and nitrogen dioxide have been identified as major air pollutants.

The AQI standard for ozone and particle pollution according to US EPA comprises of six categories. Each category is assigned a specific colour and corresponds to a different level of health concern. As the scale grows the air quality turns from good to extremely unhealthy.

 
Weekly Air Quality in Selected Towns of Sri Lanka (15 – 21 December 2025)

Access to real- time air quality data from laser air quality sensoring instruments operated by FECT is available at www.cleanair.lk