An AQI between 0 and 50 is considered 'good', 51 and 100 'satisfactory', 101 and 200 'moderate', 201 and 300 'poor', 301 and 400 'very poor', and 401 and 500 'severe'. A slight improvement has been noticed and it can be attributed to the impact of the easterlies that have reduced the impact of the northwesterlies.