| S/N | Causal Factors | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | Score | Rank |
| 1 | Incidence of pollution | 304 | 220 | 206 | 85 | 75 |
|
|
|
| 2073 | 1 |
| 2 | Gas flaring | 301 | 240 | 186 | 103 | 70 |
|
|
|
| 2101 | 2 |
| 3 | Industrial pollution | 220 | 201 | 200 | 171 | 108 |
|
|
|
| 2446 | 3 |
| 4 | Thermal pollution | 75 | 119 | 122 | 150 | 160 | 224 |
|
|
| 3423 | 4 |
| 5 | Erosion |
| 120 | 120 | 160 | 230 | 260 |
|
|
| 3950 | 5 |
| 6 | Siltation |
|
| 66 | 130 | 134 | 140 | 200 | 230 |
| 5468 | 6 |
| 7 | Physical obstruction of water ways by waste and equipment |
|
|
| 60 | 67 | 116 | 196 | 221 | 240 | 6561 | 7 |
| 8 | Sewage pollution |
|
|
| 44 | 50 | 150 | 200 | 221 | 235 | 6550 | 8 |
| 9 | Flooding |
|
|
|
| 4 | 10 | 233 | 228 | 425 | 7360 | 9 |