GUWAHATI: As per Pollution Control Board of Assam (PCBA) data, the air quality index (AQI) as recorded in six different monitoring stations was 144 in March, 2019. In April, the quality of air improved and the AQI became 104 and further reduced to 62 on May this year. The AQI records the level of pollution contained in the atmosphere which has effects on our health. If the AQI is between 50 to 100, it is considered satisfactory. However, if it reaches the 100 to 200 range, it is considered moderate and causes breathing problems. The decrease in AQI bodes good news for the city residents as it means that the air is cleaner.