| Level | Geo-accumulation index | Pollution levels |
| 1 | Igeo ≤ 0 | No pollution |
| 2 | 0 ≤ Igeo ≤ 1 | Slight pollution |
| 3 | 1 ≤ Igeo ≤ 2 | Towards moderate pollution |
| 4 | 2 ≤ Igeo ≤ 3 | Moderate pollution |
| 5 | 3 ≤ Igeo ≤ 4 | Towards serious pollution |
| 6 | 4 ≤ Igeo ≤ 5 | Serious pollution |
| 7 | Igeo > 5 | Extremely serious pollution |